National Cancer Institute


Expert-reviewed information summary about the treatment of childhood soft tissue sarcomas.

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of childhood soft tissue sarcoma. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.

This summary is reviewed regularly and updated as necessary by the PDQ Pediatric Treatment Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).

Childhood Soft Tissue Sarcoma Treatment

General Information About Childhood Soft Tissue Sarcoma

Dramatic improvements in survival have been achieved for children and adolescents with cancer. Between 1975 and 2010, childhood cancer mortality decreased by more than 50%. Childhood and adolescent cancer survivors require close monitoring because cancer therapy side effects may persist or develop months or years after treatment. (Refer to the PDQ summary on Late Effects of Treatment for Childhood Cancer for specific information about the incidence, type, and monitoring of late effects in childhood and adolescent cancer survivors.)

Rhabdomyosarcoma, a tumor of striated muscle, is the most common soft tissue sarcoma in children aged 0 to 14 years and accounts for 50% of tumors in this age group. (Refer to the PDQ summary on Childhood Rhabdomyosarcoma Treatment for more information.) In pediatrics, the remaining soft tissue sarcomas are commonly referred to as nonrhabdomyosarcomatous soft tissue sarcomas and account for approximately 3% of all childhood tumors. This heterogeneous group of tumors includes the following neoplasms:

  • Connective tissue (e.g., desmoid-type fibromatosis).
  • Peripheral nervous system (e.g., malignant peripheral nerve sheath tumor).
  • Smooth muscle (e.g., leiomyosarcoma).
  • Vascular tissue (blood and lymphatic vessels, e.g., angiosarcoma). (Refer to the PDQ summary on Childhood Vascular Tumors Treatment for more information about childhood vascular tumors.)

Distribution of Soft Tissue Sarcoma by Age and Histology

Pediatric soft tissue sarcomas are a heterogenous group of malignant tumors that originate from primitive mesenchymal tissue and account for 7% of all childhood tumors.

The distribution of soft tissue sarcomas by histology and age, based on the Surveillance, Epidemiology, and End Results (SEER) information from 1975 to 2012, is depicted in Table 1. The distribution of histologic subtypes by age is also shown in Figure 2.

Nonrhabdomyosarcomatous soft tissue sarcomas are more common in adolescents and adults, and most of the information regarding treatment and natural history of the disease in younger patients has been based on adult studies. The distributions of these tumors by age according to stage, histologic subtype, and tumor site are shown in Figures 1, 2, and 3, respectively.

Chart showing the distribution of nonrhabdomyosarcomatous soft tissue sarcomas by age according to stage.Figure 1. The distribution of nonrhabdomyosarcomatous soft tissue sarcomas by age according to stage.

Chart showing the distribution of nonrhabdomyosarcomatous soft tissue sarcomas by age according to histologic subtype.Figure 2. The distribution of nonrhabdomyosarcomatous soft tissue sarcomas by age according to histologic subtype.

Chart showing the distribution of nonrhabdomyosarcomatous soft tissue sarcomas by age according to tumor site.Figure 3. The distribution of nonrhabdomyosarcomatous soft tissue sarcomas by age according to tumor site.

Risk Factors

Some genetic and environmental factors have been associated with the development of nonrhabdomyosarcomatous soft tissue sarcoma, including the following:

  • Genetic factors:
    • Li-Fraumeni syndrome: Patients with Li-Fraumeni syndrome (usually due to heritable cancer-associated changes of the tumor suppressor gene) have an increased risk of developing soft tissue tumors (mostly nonrhabdomyosarcomatous soft tissue sarcomas), bone sarcomas, breast cancer, brain tumors, and acute leukemia.
    • Familial adenomatous polyposis: Patients with familial adenomatous polyposis are at increased risk of developing desmoid-type fibromatosis.
    • () gene: Germline mutations of the gene have been associated with an increased risk of developing soft tissue sarcomas, particularly leiomyosarcoma.
    • gene: Germline mutations or deletions of the () gene are associated with an increased risk of developing extrarenal rhabdoid tumors.
    • Neurofibromatosis type 1: Approximately 4% of patients with neurofibromatosis type 1 develop malignant peripheral nerve sheath tumors, which usually develop after a long latency; some patients develop multiple lesions.
    • Werner syndrome: Werner syndrome is characterized by spontaneous chromosomal instability, resulting in increased susceptibility to cancer and premature aging. An excess of soft tissue sarcomas has been reported in patients with Werner syndrome.
  • Environmental factors:
    • Radiation: Some nonrhabdomyosarcomatous soft tissue sarcomas (particularly malignant fibrous histiocytoma) can develop within a previously irradiated site.
    • Epstein-Barr virus infection in patients with AIDS: Some nonrhabdomyosarcomatous soft tissue sarcomas (e.g., leiomyosarcoma) have been linked to Epstein-Barr virus infection in patients with AIDS.

Clinical Presentation

Although nonrhabdomyosarcomatous soft tissue sarcomas can develop in any part of the body, they arise most commonly in the trunk and extremities. These neoplasms can present initially as an asymptomatic solid mass, or they may be symptomatic because of local invasion of adjacent anatomical structures. Although rare, these tumors can arise primarily in brain tissue and are treated according to the histiotype.

Systemic symptoms (e.g., fever, weight loss, and night sweats) are rare. Hypoglycemia and hypophosphatemic rickets have been reported in cases of hemangiopericytoma, whereas hyperglycemia has been noted in patients with fibrosarcoma of the lung.

Diagnostic and Staging Evaluation

When a suspicious lesion is identified, it is crucial that a complete workup, followed by adequate biopsy be performed. It is best to image the lesion using the following procedures before initiating any intervention:

  • Plain films. Plain films can be used to rule out bone involvement and detect calcifications that may be seen in soft tissue tumors such as extraskeletal osteosarcoma or synovial sarcoma.
  • Chest computed tomography (CT). Chest CT is essential to assess the presence of metastases.
  • Abdominal CT or magnetic resonance imaging (MRI). Abdominal CT or MRI can be used to image intra-abdominal tumors, such as liposarcoma.
  • Extremity MRI. MRI is essential for extremity lesions.
  • Positron emission tomography (PET) scan and bone scan. In children with rhabdomyosarcoma, PET-CT performed better than conventional imaging in identifying nodal, bone, bone marrow, and soft tissue disease. The authors of an imaging comparison study suggest that bone scans with technetium Tc 99m might be eliminated as a staging procedure. The use of this modality in pediatric nonrhabdomyosarcomatous soft tissue sarcoma has not been studied extensively. However, a small study of nine patients with nonrhabdomyosarcomatous soft tissue sarcoma suggests that PET-CT is more accurate and cost effective than either modality alone in identifying distant metastatic disease.

The imaging characteristics of some tumors can be highly suggestive of this diagnosis. For example, the imaging characteristics of pediatric low-grade fibromyxoid sarcoma and alveolar soft part sarcoma have been described and can aid in the diagnosis of these rare neoplasms.

Biopsy strategies

Although nonrhabdomyosarcomatous soft tissue tumors are fairly readily distinguished pathologically from rhabdomyosarcoma and Ewing sarcoma, the classification of childhood nonrhabdomyosarcomatous soft tissue sarcoma type is often difficult. Core-needle biopsy, incisional biopsy, or excisional biopsy can be used to diagnose a nonrhabdomyosarcomatous soft tissue sarcoma. If possible, the surgeon who will perform the definitive resection needs to be involved in the biopsy decision. Poorly placed incisional or needle biopsies may adversely affect the performance of the primary resection.

Considerations related to the selection of a biopsy procedure are as follows:

  • Given the diagnostic importance of translocations, a core-needle biopsy or small incisional biopsy that obtains adequate tumor tissue is crucial to allow for conventional histology, immunocytochemical analysis, and other studies such as light and electron microscopy, cytogenetics, fluorescence hybridization, and molecular pathology. Core-needle biopsy for a deep-seated tumor can lead to formation of a hematoma, which affects subsequent resection and/or radiation; in these cases, incisional biopsy is the preferred procedure.
  • Fine-needle biopsy is usually not recommended because it is difficult to determine the accurate histologic diagnosis and grade of the tumor in this heterogeneous group of tumors.
  • Image guidance using ultrasound, CT scan, or MRI may be necessary to ensure a representative biopsy.
  • Needle biopsy techniques must ensure adequate tissue sampling. The acquisition of multiple cores of tissue may be required.
  • Incisional biopsies must not compromise subsequent wide local excision.
  • Excisional biopsy of the lesion is only appropriate for small superficial lesions (<3 cm in size) and are discouraged. If an excisional biopsy is contemplated, then MRI of the area is recommended to define the area of involvement as subsequent surgery or radiation therapy is likely.
  • Various institutional series have demonstrated the feasibility and effectiveness of sentinel node biopsy as a staging procedure in pediatric patients with soft tissue sarcomas.
  • Transverse extremity incisions are avoided to reduce skin loss and because they require a greater cross-sectional volume of tissue to be covered in the radiation field. Other extensive surgical procedures are also avoided before definitive diagnosis. For these reasons, open biopsy or multiple core-needle biopsies are strongly encouraged so that adequate tumor tissue can be obtained to allow crucial studies to be performed and to avoid limiting future treatment options.

Unplanned resection

In children with unplanned resection of nonrhabdomyosarcomatous soft tissue sarcomas, primary re-excision is frequently recommended because many patients will have tumor present in the re-excision specimen. A single-institution analysis of adolescents and adults compared patients with unplanned excision of soft tissue sarcoma to stage-matched controls. In this retrospective analysis, unplanned initial excision of soft tissue sarcoma resulted in increased risk of local recurrence, metastasis, and death; this increase was greatest for high-grade tumors.[]

Chromosomal abnormalities

Many nonrhabdomyosarcomatous soft tissue sarcomas are characterized by chromosomal abnormalities. Some of these chromosomal translocations lead to a fusion of two disparate genes. The resulting fusion transcript can be readily detected by using polymerase chain reaction-based techniques, thus facilitating the diagnosis of those neoplasms that have translocations.

Some of the most frequent aberrations seen in nonrhabdomyosarcomatous soft tissue tumors are listed in Table 2.

Prognosis

The prognosis of nonrhabdomyosarcomatous soft tissue sarcoma varies greatly depending on the following factors:

  • Site of the primary tumor.
  • Tumor size.
  • Tumor grade. (Refer to the Prognostic Significance of Tumor Grading section of this summary for more information.)
  • Tumor histology.
  • Depth of tumor invasion.
  • Presence of metastases.
  • Resectability of the tumor.
  • Use of radiation therapy.

Several adult and pediatric series have shown that patients with large or invasive tumors have a significantly worse prognosis than do those with small, noninvasive tumors. A retrospective review of soft tissue sarcomas in children and adolescents suggests that the 5 cm cutoff used for adults with soft tissue sarcoma may not be ideal for smaller children, especially infants. The review identified an interaction between tumor diameter and body surface area. This relationship requires further study to determine the therapeutic implications of the observation.

In a review of a large adult series of nonrhabdomyosarcomatous soft tissue sarcomas, superficial extremity sarcomas had a better prognosis than did deep tumors. Thus, in addition to grade and size, the depth of invasion of the tumor should be considered.

Some pediatric nonrhabdomyosarcomatous soft tissue sarcomas are associated with a better outcome. For instance, infantile fibrosarcoma, presenting in infants and children younger than 5 years, has an excellent prognosis given that surgery alone can cure a significant number of these patients and the tumor is highly chemosensitive.

Soft tissue sarcomas in older children and adolescents often behave similarly to those in adult patients. A large, prospective, multinational Children's Oncology Group study () enrolled newly diagnosed patients younger than 30 years. Patients were assigned to treatment on the basis of their risk group (refer to Figure 4).[]

Chart showing risk stratification and treatment assignment for the Children's Oncology Group ARST0332 trial.Figure 4. Risk stratification and treatment assignment for the Children's Oncology Group ARST0332 trial. Credit: Sheri L. Spunt, M.D., M.B.A.

Of 551 patients enrolled, at a median follow-up of 2.6 years, the preliminary analysis estimated the following 3-year survival rates:

  • Arm A: 91% event-free survival (EFS); 99% overall survival (OS).
  • Arm B: 79% EFS; 100% OS.
  • Arm C: 68% EFS; 81% OS.
  • Arm D: 52% EFS; 66% OS.

Pediatric patients with unresected localized nonrhabdomyosarcomatous soft tissue sarcomas have a poor outcome. Only about one-third of patients treated with multimodality therapy remain disease free.; [] In a review of 30 Italian patients with nonrhabdomyosarcomatous soft tissue sarcoma at visceral sites (mesentery-bowel, lung-pleura, liver, and kidney), only 10 patients survived at 5 years. Unfavorable prognostic factors were inability to achieve complete resection, large tumor size, tumor invasion, histologic subtype, and lung-pleura sites. Patients with completely resected disease had a 75% survival rate at 5 years, while patients with residual disease had a 16.7% survival rate.[]

In a pooled analysis from U.S. and European pediatric centers, outcome was better for patients whose tumor removal procedure was deemed complete than for patients whose tumor removal was incomplete. Outcome was better for patients who received radiation therapy than for patients who did not.[]

Because long-term related morbidity must be minimized while disease-free survival is maximized, the ideal therapy for each patient must be carefully and individually determined utilizing these prognostic factors before initiating therapy.

Related Summaries

Refer to the following PDQ summaries for information about other types of sarcoma:

  • Childhood Rhabdomyosarcoma Treatment.
  • Childhood Vascular Tumors Treatment.
  • Ewing Sarcoma Treatment (extraosseous Ewing, peripheral neuroepithelioma, and Askin tumors).
  • Unusual Cancers of Childhood Treatment (gastrointestinal stromal tumors).
  • Adult Soft Tissue Sarcoma Treatment.

Histopathological Classification of Childhood Soft Tissue Sarcoma

World Health Organization (WHO) Classification of Soft Tissue Sarcomas

The WHO lists the following cell types in its classification of soft tissue sarcomas:

Staging and Grading Systems for Childhood Soft Tissue Sarcoma

Clinical staging has an important role in predicting the clinical outcome and determining the most effective therapy for pediatric soft tissue sarcomas. As yet, there is no well-accepted staging system that is applicable to all childhood sarcomas. The system from the American Joint Committee on Cancer (AJCC) that is used for adults has not been validated in pediatric studies. Although a standardized staging system for pediatric nonrhabdomyosarcomatous soft tissue sarcoma does not exist, two systems are currently in use for staging pediatric nonrhabdomyosarcomatous soft tissue sarcoma.

  • Surgico-pathologic staging system: The surgico-pathologic staging system used by the Intergroup Rhabdomyosarcoma Study (see below) is based on the amount, or extent, of tumor that remains after initial surgery and whether the disease has metastasized. This staging system was used in early pediatric trials.
  • TNM staging system: The TNM staging system is a collaborative effort between the AJCC (United States) and the International Union Against Cancer (worldwide). Staging is based on the extent of the tumor (T), the extent of spread to the lymph nodes (N), and the presence of metastasis (M). Refer to Tables 3, 4, 5, and 6 for the staging of soft tissue sarcoma from the eighth edition of the AJCC Cancer Staging Manual. The last Children's Oncology Group trial used the sixth edition AJCC Cancer Staging Manual for soft tissue sarcoma (with central pathology review). A review of children with non-rhabdomyosarcoma soft tissue sarcomas was performed with data from the Surveillance, Epidemiology, and End Results (SEER) program and identified 941 patients between 1988 and 2007. The COG risk stratification was validated in this cohort.

Intergroup Rhabdomyosarcoma Study Staging System

Nonmetastatic disease

  • Group I: Localized tumor completely resected with histologically negative margins.
  • Group II: Grossly resected tumor with microscopic residual tumor at the margin(s) and/or extension into regional lymph nodes.
    • IIA: Localized, grossly resected tumor with microscopic residual disease.
    • IIB: Regional disease with involved nodes completely resected with no microscopic disease. The most proximal (to the patient, most distal to the tumor) regional lymph node must be negative.
    • IIC: Regional disease with involved nodes grossly resected but with evidence of residual microscopic disease at the primary site and/or histologic involvement of the most proximal regional lymph node in the dissection.
  • Group III: Localized tumor, incompletely resected, or biopsy only, with gross residual tumor.

Metastatic disease

  • Group IV: Any localized or regional tumor with distant metastases present at the time of diagnosis. This includes the presence of malignant cells in effusions (pleural, peritoneal) and/or cerebrospinal fluid (rare).

Recurrent/progressive disease

  • Any soft tissue sarcoma that recurs after initial treatment or progresses after radiation therapy, chemotherapy, or initial surgery.

TNM Staging System

The eighth edition of the AJCC Cancer Staging Manual has designated staging by the four criteria of tumor size, nodal status, histologic grade, and metastasis and by anatomic primary tumor site (head and neck; trunk and extremities; abdomen and thoracic visceral organs; retroperitoneum; and unusual histologies and sites) (refer to Tables 3, 4, 5, and 6). For information on unusual histologies and sites, refer to the AJCC Cancer Staging Manual.

Soft Tissue Sarcoma Tumor Pathological Grading System

In most cases, accurate histopathologic classification alone of soft tissue sarcomas does not yield optimal information about their clinical behavior. Therefore, several histologic parameters are evaluated in the grading process, including the following:

  • Degree of cellularity.
  • Cellular pleomorphism.
  • Mitotic activity.
  • Degree of necrosis.
  • Invasive growth.

This process is used to improve the correlation between histologic findings and clinical outcome. In children, grading of soft tissue sarcoma is compromised by the good prognosis of certain tumors, such as infantile fibrosarcoma and hemangiopericytoma, which have a good prognosis in children younger than 4 years, and also angiomatoid fibrous histiocytoma and dermatofibrosarcoma protuberans, which may recur locally if incompletely excised, but usually do not metastasize.

Testing the validity of a grading system within the pediatric population is difficult because of the rarity of these neoplasms. In March 1986, the Pediatric Oncology Group (POG) conducted a prospective study on pediatric soft tissue sarcomas other than rhabdomyosarcoma and devised the POG grading system. Analysis of outcome for patients with localized soft tissue sarcomas other than rhabdomyosarcoma demonstrated that patients with grade 3 tumors fared significantly worse than those with grade 1 or grade 2 lesions. This finding suggests that this system can accurately predict the clinical behavior of nonrhabdomyosarcomatous soft tissue sarcoma.

The grading systems developed by the POG and the French Federation of Comprehensive Cancer Centers (Fédération Nationale des Centres de Lutte Contre Le Cancer [FNCLCC]) Sarcoma Group are described below. These grading systems are being compared by the central review pathologists on the study. The study has closed and results are pending.

POG grading system

The POG grading system is described below. It is an older grading system of historical value that is no longer being used for treatment.

Grade I

Grade I lesions are based on histologic type, well-differentiated cytohistologic features, and/or age of the patient.

  • Angiomatoid fibrous histiocytoma.
  • Dermatofibrosarcoma protuberans.
  • Liposarcoma–myxoid or well-differentiated.
  • Myxoid chondrosarcoma.
  • Well-differentiated malignant peripheral nerve sheath tumor.
  • Well-differentiated or infantile (aged ≤4 years) fibrosarcoma.
  • Well-differentiated or infantile (aged ≤4 years) hemangiopericytoma.

Grade II

Grade II lesions are soft tissue sarcomas not included in grade I or III by histologic diagnosis (with <5 mitoses/10 high-power fields or <15% necrosis):

  • 15% or less of the surface area shows necrosis (primary criteria).
  • The mitotic count is <5 mitotic figures per 10 high-power fields (40X objective) (primary criteria).
  • Nuclear atypia is not marked (secondary criteria).
  • The tumor is not markedly cellular (secondary criteria).

Grade III

Grade III lesions are similar to grade II lesions and include certain tumors known to be clinically aggressive by virtue of histologic diagnosis and non-grade I tumors (with >4 mitoses per 10 high-power fields or >15% necrosis):

  • Alveolar soft part sarcoma.
  • Extraskeletal osteogenic sarcoma.
  • Malignant triton tumor.
  • Mesenchymal chondrosarcoma.
  • Pleomorphic or round-cell liposarcoma.
  • Any other sarcoma not in grade I with >15% necrosis and/or ≥5 mitotic figures per 10 high-power fields (40X objective). Marked atypia and cellularity are less predictive but may assist in placing tumors in this category.

FNCLCC grading system

The FNCLCC histologic grading system was developed for adults with soft tissue sarcoma. The purpose of the grading system is to predict which patients will develop metastasis and subsequently benefit from postoperative chemotherapy. The system is described in Table 7 and Table 8.

Prognostic Significance of Tumor Grading

The POG and FNCLCC grading systems have proven to be of prognostic value in pediatric and adult nonrhabdomyosarcomatous soft tissue sarcomas. In a study of 130 tumors from children and adolescents with nonrhabdomyosarcomatous soft tissue sarcoma enrolled in three prospective clinical trials, a correlation was found between the POG-assigned grade and the FNCLCC-assigned grade. However, grading did not correlate in all cases; 44 patients whose tumors received discrepant grades (POG grade 3, FNCLCC grade 1 or 2) had outcomes between concurrent grade 3 and grades 1 and 2. A mitotic index of 10 or greater emerged as an important prognostic factor. The recently completed trial will analyze data comparing the POG and FNCLCC pathologic grading systems to determine which system better correlates with clinical outcomes. The current open trial () uses the FNCLCC system to assign histological grade.

Treatment Option Overview for Childhood Soft Tissue Sarcoma

Because of the rarity of pediatric nonrhabdomyosarcomatous soft tissue sarcomas, coordination of treatment by a multidisciplinary team comprising oncologists (pediatric or medical), pathologists, surgeons, and radiation oncologists should be considered for all children, adolescents, and young adults with these tumors. In addition, to better define the tumors' natural history and response to therapy, entry into national or institutional treatment protocols should be considered for children with rare neoplasms. Information about ongoing clinical trials is available from the NCI website.

Surgery

After an appropriate biopsy and pathologic diagnosis, every attempt is made to resect the primary tumor with negative margins before or after chemotherapy and/or radiation therapy. Involvement of a surgeon with special expertise in the resection of soft tissue sarcomas in the decision is highly desirable.

The timing of surgery depends on an assessment of the feasibility and morbidity of surgery. If the initial operation fails to achieve pathologically negative tissue margins or if the initial surgery was done without the knowledge that cancer was present, a re-excision of the affected area is performed to obtain clear, but not necessarily wide, margins. This surgical tenet is true even if no mass is detected by magnetic resonance imaging after initial surgery.; []

Regional lymph node metastases at diagnosis are unusual and are most often seen in patients with epithelioid and clear cell sarcomas. Various institutional series have demonstrated the feasibility and effectiveness of sentinel node biopsy as a staging procedure in pediatric patients with soft tissue sarcomas.

Radiation Therapy

Considerations for radiation therapy are based on the potential for surgery, with or without chemotherapy, to obtain local control without loss of critical organs or significant functional, cosmetic, or psychological impairment. This will vary according to the following:

  • Patient variables (e.g., age and sex).
  • Tumor variables (e.g., histopathology, site, size, and grade).
  • Surgical margin status.
  • Expectations for radiation-induced morbidities (e.g., impaired bone or muscle development, organ damage, or second malignancy).

Radiation therapy can be given preoperatively. Radiation field size and dose will be based on patient and tumor variables and the operability of the tumor. Preoperative radiation therapy has been associated with excellent local control rates. This approach has the advantage of treating smaller tissue volumes because it does not necessitate treating a postsurgical bed; it also has the advantage of somewhat lower radiation doses because relative hypoxia from surgical disruption of vasculature and scarring is not present. Preoperative radiation therapy has been associated with an increased rate of wound complications in adults, primarily in lower extremity tumors, but the degree of this is questionable. Conversely, preoperative radiation therapy may lead to less fibrosis than with postoperative approaches, perhaps due to the smaller treatment volume and dose.

Retroperitoneal sarcomas are unique in that radiosensitivity of the bowel to injury makes postoperative radiation therapy less desirable. Postoperative adhesions and bowel immobility can increase the risk of damage from any given radiation dose. This contrasts with the preoperative approach in which the tumor often displaces bowel outside of the radiation field, and any exposed bowel is more mobile, which decreases exposure to specific bowel segments.

Radiation therapy can also be given postoperatively. In general, radiation is indicated for patients with inadequate surgical margins and for larger, high-grade tumors. This is particularly important in high-grade tumors with tumor margins smaller than 1 cm.; [] With combined surgery and radiation therapy, local control of the primary tumor can be achieved in more than 80% of patients.

Brachytherapy and intraoperative radiation may be applicable in select situations.; []

Radiation volume and dose depend on the patient, tumor, and surgical variables noted above, as well as the following:

  • Patient age and growth potential.
  • Ability to avoid critical organs, epiphyseal plates, and lymphatics (but not the neurovascular bundles that are relatively radiation tolerant).
  • Functional/cosmetic outcome.

Radiation doses are typically 45 Gy to 50 Gy preoperatively, with consideration for postoperative boost of 10 Gy to 20 Gy if resection margins are microscopically or grossly positive, or planned brachytherapy if the resection is predicted to be subtotal. However, data documenting the efficacy of a postoperative boost are lacking. The postoperative radiation dose is 55 Gy to 60 Gy, or rarely, higher when unresectable gross residual disease exists.

Radiation margins are typically 2 cm to 4 cm longitudinally and encompass fascial planes axially.

Chemotherapy

The role of postoperative chemotherapy remains unclear as evidenced by the following studies:

  • A meta-analysis of data from all randomized trials of adults with soft tissue sarcoma concluded that recurrence-free survival was better with postoperative chemotherapy for patients with high-grade tumors larger than 5 cm.
  • In a European trial, adults with completely resected soft tissue sarcoma were randomly assigned to observation or postoperative chemotherapy with ifosfamide and doxorubicin. Postoperative chemotherapy was not associated with improved event-free survival (EFS) or overall survival (OS). It is difficult to extrapolate this trial to pediatric patients because the trial included 1) a wide variety of histologies; 2) a relatively low dose of ifosfamide; 3) patients assigned to chemotherapy had definitive radiation delayed until completion of chemotherapy; and 4) almost one-half of the patients in the trial had intermediate-grade tumors. In the discussion section, the authors merged their patients with previously published series, including those from the European meta-analysis, and concluded that the results suggested a benefit for postoperative chemotherapy.[]
  • The largest prospective pediatric trial failed to demonstrate any benefit with postoperative vincristine, dactinomycin, cyclophosphamide, and doxorubicin.
  • Doxorubicin and ifosfamide were used in the risk-based COG trial. Although this was not a randomized study, results at 2.6 years show that patients with high-risk (>5 cm and high grade), grossly resected, nonmetastatic tumors who were treated with radiation therapy and postoperative doxorubicin and ifosfamide had a 3-year EFS of 68% and OS of 81%. In patients with metastatic disease treated with preoperative chemotherapy and radiation therapy, the estimated 3-year failure-free survival was 52% and OS was 66%.[]

Targeted Therapy

The use of angiogenesis and mammalian target of rapamycin (mTOR) inhibitors has been explored in the treatment of adult soft tissue sarcomas but not in pediatrics.

  • In a trial of 711 randomly assigned adult patients who achieved a response or stable disease after chemotherapy, the administration of ridaforolimus was associated with a 3-week improvement in progression-free survival (PFS) when compared with placebo.
  • In another trial of 371 randomly assigned adult patients with metastatic soft tissue sarcoma that progressed after chemotherapy, pazopanib was compared with placebo. The median PFS for the pazopanib arm was 4.6 months compared with 1.6 months for the placebo arm. OS was not different between the two arms.
  • In a randomized study of 182 previously treated adult patients with recurrent liposarcoma, leiomyosarcoma, synovial sarcoma, and other sarcomas, patients with nonadipocytic tumors who were treated with regorafenib had significant improvements in progression-free survival when compared with patients who were treated with placebo.

Special Considerations for the Treatment of Children With Soft Tissue Sarcoma

Cancer in children and adolescents is rare, although the overall incidence of childhood cancer has been slowly increasing since 1975. Children and adolescents with cancer should be referred to medical centers that have a multidisciplinary team of cancer specialists with experience treating the cancers that occur during childhood and adolescence. This multidisciplinary team approach incorporates the skills of the following health care professionals and others to ensure that children receive treatment, supportive care, and rehabilitation that will achieve optimal survival and quality of life:

  • Primary care physicians.
  • Pediatric surgical specialists.
  • Pediatric radiation oncologists.
  • Pediatric medical oncologists/hematologists.
  • Rehabilitation specialists.
  • Pediatric nurse specialists.
  • Social workers.
  • Child life professionals.
  • Psychologists.

(Refer to the PDQ Supportive and Palliative Care summaries for specific information about supportive care for children and adolescents with cancer.)

Guidelines for pediatric cancer centers and their role in the treatment of pediatric patients with cancer have been outlined by the American Academy of Pediatrics. At these pediatric cancer centers, clinical trials are available for most types of cancer that occur in children and adolescents, and the opportunity to participate in these trials is offered to most patients/families. Multidisciplinary evaluation in pediatric cancer centers that have surgical and radiotherapeutic expertise is of critical importance to ensure the best clinical outcome for these patients. Although surgery with or without radiation therapy can be curative for a significant proportion of patients, the addition of chemotherapy might benefit subsets of children with the disease; therefore, enrollment into clinical trials is encouraged. Clinical trials for children and adolescents with cancer are generally designed to compare potentially better therapy with therapy that is currently accepted as standard. Most of the progress made in identifying curative therapies for childhood cancers has been achieved through clinical trials. Information about ongoing clinical trials is available from the NCI website.

Many therapeutic strategies for children and adolescents with soft tissue tumors are similar to those for adult patients, although there are important differences. For example, the biology of the neoplasm in pediatric patients may differ dramatically from that of the adult lesion. Additionally, limb-sparing procedures are more difficult to perform in pediatric patients. The morbidity associated with radiation therapy, particularly in infants and young children, may be much greater than that observed in adults.

Improved outcomes with multimodality therapy in adults and children with soft tissue sarcomas over the past 20 years has caused increasing concern about the potential long-term side effects of this therapy in children, especially when considering the expected longer life span of children versus adults. Therefore, to maximize tumor control and minimize long-term morbidity, treatment must be individualized for children and adolescents with nonrhabdomyosarcomatous soft tissue sarcoma. These patients should be enrolled in prospective studies that accurately assess any potential complications.

Treatment of Newly Diagnosed Childhood Soft Tissue Sarcoma

Adipocytic Tumors

Liposarcoma

Liposarcoma accounts for 3% of soft tissue sarcoma in patients younger than 20 years (refer to Table 1).

Liposarcoma is rare in the pediatric population. In a review of 182 pediatric patients with adult-type sarcomas, only 14 had a diagnosis of liposarcoma. One retrospective study identified 34 patients younger than 22 years from 1960 to 2011. There were roughly equal numbers of male and female patients and the median age was 18 years. In an international clinicopathological review, the characteristics of 82 cases of pediatric liposarcoma were reported. The median age was 15.5 years and females were more commonly affected. In both reports, the great majority of patients had myxoid liposarcoma.

Histopathologic classification

The World Health Organization (WHO) classification for liposarcoma is as follows:

Clinical presentation

The majority of liposarcomas in the pediatric and adolescent age range are low grade and located subcutaneously. Metastasis to lymph nodes is very uncommon, and the great majority of metastases are pulmonary. Tumors arising in the periphery are more likely to be low grade and myxoid. Tumors arising centrally are more likely to be high grade, pleomorphic, and present with metastasis or recur with metastasis.

Prognosis

Higher grade or central tumors are associated with a significantly higher risk of death. In a retrospective review, 5-year survival for central tumors was 42%. In the international review, seven of ten patients with pleomorphic myxoid liposarcoma died because of their disease. In a retrospective study of 14 patients, 5-year survival was 78% and tumor grade, histologic subtype, and primary location correlated with survival.

Treatment

Treatment options for liposarcoma include the following:

Surgery is the most important treatment for liposarcoma. After surgical resection of myxoid liposarcoma, event-free survival (EFS) and overall survival (OS) are roughly 90%. If initial surgery is incomplete, re-excision should be performed to achieve a wide margin of resection. Local recurrences have been seen and are controlled with a second resection of the tumor.

There are reports of the use of chemotherapy to decrease the size of liposarcoma before surgery to facilitate complete resection, particularly in central tumors. The role of postoperative chemotherapy for liposarcoma is poorly defined. There does not appear to be a need for any postoperative therapy for completely resected myxoid liposarcoma. Even with the use of postoperative chemotherapy, the survival of pleomorphic liposarcoma remains poor.

Trabectedin has produced encouraging responses in adults with advanced myxoid liposarcoma. In one study, adult patients with recurrent liposarcoma and leiomyosarcoma were randomly assigned to treatment with either trabectedin or dacarbazine. Patients treated with trabectedin had a 45% reduction in disease progression.[] There are very limited data to support the use of trabectedin in pediatric patients.

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma, excluding myxoid liposarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with liposarcoma are eligible for this trial.

Chondro-osseous Tumors

Chondro-osseous tumors include the following tumor subtypes:

  • Extraskeletal mesenchymal chondrosarcoma.
  • Extraskeletal osteosarcoma.
  • Soft tissue chondroma.

Extraskeletal mesenchymal chondrosarcoma

Osseous and chondromatous neoplasms account for 0.8% of soft tissue sarcoma in patients younger than 20 years (refer to Table 1).

Histopathology and molecular features

Mesenchymal chondrosarcoma is a rare tumor characterized by small round cells and hyaline cartilage that more commonly affects young adults and has a predilection for involving the head and neck region.

Mesenchymal chondrosarcoma has been associated with consistent chromosomal rearrangement. A retrospective analysis of cases of mesenchymal chondrosarcoma identified a fusion in 10 of 15 tested specimens. This gene fusion was not associated with chromosomal changes that could be detected by karyotyping. In one instance, translocation t(1;5)(q42;q32) was identified in a case of mesenchymal chondrosarcoma and shown to be associated with a novel fusion gene.

Prognosis

A retrospective survey of European institutions identified 113 children and adults with mesenchymal chondrosarcoma. Factors associated with better outcome included the following:[]

  • Lack of metastatic disease at initial presentation.
  • Clear resection margins.
  • Administration of postoperative chemotherapy following resection for patients with initially localized disease.

Treatment

Treatment options for extraskeletal mesenchymal chondrosarcoma include the following:

A review of 15 patients younger than 26 years from the German Cooperative Soft Tissue Sarcoma Study Group (11 with soft-tissue lesions) and the German-Austrian-Swiss Cooperative Osteosarcoma Study Group (four with primary bone lesions) protocols suggests that complete surgical removal, or incomplete resection followed by radiation therapy, is necessary for local control.[]

A single-institution, retrospective review identified 12 pediatric patients with mesenchymal chondrosarcoma. The presence of the rearrangement in tumors was documented in these patients. It was also confirmed that surgical resection is necessary for cure. Eleven patients presented with localized disease and one presented with pulmonary nodules. All patients received chemotherapy—six patients before and after surgical resection and six patients only after resection. All patients received postoperative chemotherapy (most commonly ifosfamide/doxorubicin) with or without radiation therapy (median dose, 59.4 Gy). At a median follow-up of 4.8 years, 5-year disease-free survival (DFS) was 68.2% (95% CI, 39.8–96.6) and OS was 88.9% (95% CI, 66.9–100).

Extraskeletal osteosarcoma

Osseous and chondromatous neoplasms account for 0.8% of soft tissue sarcomas in patients younger than 20 years (refer to Table 1).

Extraskeletal osteosarcoma is extremely rare in the pediatric and adolescent age range. A 2003 review identified only ten case reports in the medical literature.

Prognosis

Extraskeletal osteosarcoma is associated with a high risk of local recurrence and pulmonary metastasis.

Treatment

Treatment options for extraskeletal osteosarcoma include the following:

(Refer to the PDQ summary on Osteosarcoma and Malignant Fibrous Histiocytoma of Bone Treatment for more information.)

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with extraskeletal mesenchymal chondrosarcoma and extraskeletal osteosarcoma are eligible for this trial.

Fibroblastic/Myofibroblastic Tumors

Fibroblastic/myofibroblastic tumors include the following tumor subtypes:

Desmoid-type fibromatosis

Desmoid-type fibromatosis has previously been called desmoid tumors or aggressive fibromatoses.

Risk factors

A small number of desmoid-type fibromatosis tumors may occur in association with a mutation in the () gene (associated with intestinal polyps and a high incidence of colon cancer). In a study of 519 patients older than 10 years with a diagnosis of desmoid-type fibromatosis, 39 (7.5%, a possible underestimation) were found to have familial adenomatous polyposis (FAP). The patients with FAP and desmoid-type fibromatosis were younger, more often male, and had more abdominal wall or mesenteric tumors than did patients with desmoid-type fibromatosis without FAP.

A family history of colon cancer, the presence of congenital hyperplasia of the retinal pigment epithelium, or location of the desmoid-type fibromatosis in the abdomen or abdominal wall should prompt referral to a genetic counselor. Currently, there are no general recommendations for genetic testing in children with desmoid-type fibromatosis. Pathology and molecular characteristics of the tumor only provide guidance for screening. If the tumor has a somatic mutation, screening is not necessary, because the gene mutation has not been described in this setting. If a mutation is not identified, screening for the mutation may be warranted. (Refer to the Familial Adenomatous Polyposis (FAP) section of the PDQ summary on Genetics of Colorectal Cancer for more information.)

Prognosis

Desmoid-type fibromatosis has an extremely low potential to metastasize. The tumors are locally infiltrating, and surgical control can be difficult because of the need to preserve normal structures.

These tumors have a high potential for local recurrence. Desmoid-type fibromatosis has a highly variable natural history, including well documented examples of spontaneous regression. Mutations in exon 3 of the gene are seen in over 80% of desmoid-type fibromatosis and the mutation 45F has been associated with an increased risk of disease recurrence. Repeated surgical resection can sometimes bring recurrent lesions under control.

Treatment

Evaluation of the benefit of interventions for treatment of desmoid-type fibromatosis has been extremely difficult, because desmoid-type fibromatosis has a highly variable natural history. Large adult series and smaller pediatric series have reported long periods of disease stabilization and even regression without systemic therapy.; []

Treatment options for desmoid-type fibromatosis include the following:

The treatment of choice is resection to achieve clear margins. However, a retrospective review of children who underwent surgery for desmoid-type fibromatosis at the St. Jude Children’s Research Hospital (SJCRH) reported no correlation between surgical margins and risk of recurrence.

When the diagnosis is known and complete surgical excision is not feasible, and if the tumor poses significant potential for mortality or morbidity, preoperative strategies may include the following:

  • Observation.
  • Chemotherapy.
  • Anti-estrogen therapy.
  • NSAID therapy.
  • External-beam radiation therapy.

Desmoid-type fibromatosis often behaves in a nonaggressive manner. In a study that included mostly adults with extra-abdominal primary fibromatosis, nonsurgical approaches (medical and observation) had similar 3-year EFS compared with surgery. In a subsequent study of adolescents and adults with abdominal wall aggressive fibromatosis, 102 patients were treated with a approach, of which 65 patients required no further treatment at 3 years. Approximately one-third of patients had regression of the tumor.

Chemotherapy regimens may include the following:

  • Combination chemotherapy using vinblastine and methotrexate produced objective responses in about one-third of patients with unresectable or recurrent desmoid-type fibromatosis.
  • A series of mainly adult patients with FAP and unresectable desmoid-type fibromatosis that were unresponsive to hormone therapy showed that doxorubicin plus dacarbazine followed by meloxicam (an NSAID) can be safely administered and can induce responses.
  • Pegylated liposomal doxorubicin has been used with some responses.
  • Tyrosine kinase inhibitors: A small retrospective study of adults with desmoid-type fibromatosis showed objective responses to the multi-targeted kinase inhibitor sorafenib.[] Previous studies with imatinib did not support its use.
  • The NOTCH pathway has been implicated in the development of desmoid tumors. Partial responses to the gamma secretase inhibitor PF-03084014 have been noted in adults with desmoid-type fibromatosis.[]
  • Hydroxyurea has been used successfully to treat a few patients after other treatments, but more data are needed.

Other drug therapy may include the following:

  • NSAIDs such as sulindac have been used in single cases for desmoid-type fibromatosis; the responses seen were usually disease stabilization.
  • Antiestrogen treatment, usually tamoxifen, plus sulindac has also resulted in disease stabilization. A prospective trial of the combination of tamoxifen and sulindac reported few side effects, although asymptomatic ovarian cysts were common in girls. This combination showed relatively little activity, as measured by rates of response and progression-free survival (PFS).[]

Postoperative radiation therapy is a consideration when progression would entail additional surgery that might cause functional or cosmetic compromise and if radiation is considered acceptable in terms of morbidities.

Radiation has been used for unresectable desmoid-type fibromatosis or postoperatively for tumors with inadequate resections. The potential long-term complications of radiation therapy, especially subsequent neoplasms, make using this modality less appealing in a young population.

Dermatofibrosarcoma protuberans

Dermatofibrosarcoma is a rare tumor that can be present in all age groups, but many of the reported cases arise in children. A review of 451 cases in children younger than 20 years in the SEER database found that the incidence was 1 case per 1 million, highest among black patients aged 15 to 19 years. The most common sites were trunk and extremities, which is similar to what is found in adults. Ninety-five percent of patients underwent surgery. Overall survival was 100% at 5 years, 98% at 15 years, and 97% at 30 years. Males had decreased survival compared with females ( < .05).[]

Molecular features

The tumor has a consistent chromosomal translocation t(17;22)(q22;q13) that juxtaposes the gene with the gene.

Treatment

Treatment of dermatofibrosarcoma protuberans includes the following:

Most dermatofibrosarcoma tumors can be cured by complete surgical resection. Wide excision with negative margins or Mohs or modified Mohs surgery will prevent most tumors from recurring. Despite the locally aggressive behavior of the tumor, lymph node or visceral metastasis rarely occurs.

In retrospective reviews, postoperative radiation therapy after incomplete excision may have decreased the likelihood of recurrence.

When surgical resection cannot be accomplished or the tumor is recurrent, treatment with imatinib has been effective. Because metastatic disease is more likely after multiple recurrences, radiation or other adjuvant therapy should be considered in patients with recurrence that cannot be managed surgically.

Guidelines for workup and management of dermatofibrosarcoma protuberans have been published.

Infantile fibrosarcoma

There are two distinct types of fibrosarcoma in children and adolescents: infantile fibrosarcoma (also called congenital fibrosarcoma) and fibrosarcoma that is indistinguishable from fibrosarcoma seen in adults. These are two distinct pathologic diagnoses and require different treatments. Adult-type fibrosarcoma is addressed below.

Infantile fibrosarcoma usually occurs in children younger than 1 year. It occasionally occurs in children up to age 4 years.

Clinical presentation

Infantile fibrosarcoma usually presents with a rapidly growing mass, often noted at birth or even seen in prenatal ultrasound. The tumors are often quite large at the time of presentation.

Molecular features

The tumor usually has a characteristic cytogenetic translocation t(12;15)(). Infantile fibrosarcoma shares this translocation and a virtually identical histologic appearance with mesoblastic nephroma.

Prognosis

These tumors have a low incidence of metastases at diagnosis.

Treatment

Treatment options for infantile fibrosarcoma include the following:

Complete resection is curative in the majority of patients with infantile fibrosarcoma. However, the large size of the lesion frequently makes resection without major functional consequences impossible (for instance, tumors of the extremities often require amputation for complete excision). The European pediatric group has reported that observation may also be an option in patients with group II disease after surgery. Twelve patients with group II disease received no further therapy and two patients relapsed. One patient obtained a complete remission after chemotherapy. Postoperative chemotherapy was administered to patients with higher group disease and those who progressed. In a subsequent study, only one of seven patients with group II disease progressed during observation; that patient achieved complete remission with chemotherapy.[]

Preoperative chemotherapy has made a more conservative surgical approach possible; agents active in this setting include vincristine, dactinomycin, cyclophosphamide, and ifosfamide.; []; []

Three studies of patients with infantile fibrosarcoma suggest that an alkylator-free regimen is effective and should be used as the first treatment choice in patients with macroscopic disease. Two cases with variant fusions responded to crizotinib.

A pediatric patient (aged 16 months) with refractory infantile fibrosarcoma with constitutive activation of the tropomyosin-related kinase signaling pathway from an variant gene 6– gene fusion () responded to LOXO-101, with a 90% reduction in tumor size after 2 months of treatment.

A patient aged 2 months with infantile fibrosarcoma was initially treated with chemotherapy. At disease progression, a response was seen with pazopanib.

A rare case of spontaneous regression without treatment has been reported.[]

Treatment options under clinical evaluation

The following are examples of national and/or institutional clinical trials that are currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Oral TRK Inhibitor LOXO-101 for Treatment of Advanced Pediatric Solid or Primary Central Nervous System [CNS] Tumors): A phase I trial of the pan-TRK inhibitor LOXO-101 is being conducted for children with solid tumors or brain tumors whose disease has progressed or was nonresponsive to available therapies, and for which no standard or available curative therapy exists. LOXO-101 is a highly selective inhibitor of all three TRK family kinases.
  • (Study of RXDX-101 in Children With Recurrent or Refractory Solid Tumors and Primary CNS Tumors): This is a four-part, open-label, phase I/Ib, dose-escalation study in pediatric patients with: 1) relapsed or refractory solid tumors; 2) primary CNS tumors; 3) neuroblastoma; and 4) non-neuroblastoma, extracranial solid tumors with , or gene rearrangements. The study is designed to explore the safety, maximum tolerated dose or recommended phase II dose, pharmacokinetics, and antitumor activity of entrectinib (RXDX-101).

Inflammatory myofibroblastic tumor

Inflammatory myofibroblastic tumor is a rare mesenchymal tumor that has a predilection for children and adolescents.

Clinical presentation

Inflammatory myofibroblastic tumors are rare tumors that affect soft tissues and visceral organs of children and young adults. They rarely metastasize but tend to be locally invasive. Usual anatomical sites of disease include soft tissue, lungs, spleen, colon, and breast. A review of 42 cases of pediatric inflammatory myofibroblastic tumor of the bladder was published in 2015.

Molecular features

Roughly half of inflammatory myofibroblastic tumors exhibit a clonal mutation that activates the ()-receptor tyrosine kinase gene at chromosome 2p23. and -beta kinase fusions have been identified in 8 of 11 cases (73%) who are negative for by immunohistochemistry.[]

Prognosis

Inflammatory myofibroblastic tumor recurs frequently but is rarely metastatic.

Treatment

Treatment options for inflammatory myofibroblastic tumor include the following:

Complete surgical removal, when feasible, is the mainstay of therapy. In a series of nine patients, four patients achieved continuous remission after complete resection, three patients with residual disease recurred but later achieved continuous remission, and one patient with metastatic disease responded to multiagent chemotherapy.[] The benefit of chemotherapy has been noted in case reports. There are case reports of response to either steroids or NSAIDs.

Two adults with -rearranged inflammatory myofibroblastic tumor achieved partial response with crizotinib.[] For pediatric patients with measurable disease the use of crizotinib achieved partial tumor responses in three of six patients with -translocated inflammatory myofibroblastic tumors. The use of crizotinib for -rearranged non-small cell lung carcinoma suggests that this agent may be efficacious in -rearranged tumors. In a phase I trial of ceritinib for adult patients previously treated with inhibitors, one patient with inflammatory myofibroblastic tumor had a partial response.

Adult-type fibrosarcoma

These tumors lack the translocation seen in infantile fibrosarcomas. They present like the great majority of nonrhabdomyosarcomas and the management approach is similar.

Low-grade fibromyxoid sarcoma

Low-grade fibromyxoid sarcoma is a histologically deceptive soft tissue neoplasm that most commonly affects young and middle-aged adults, is commonly located deep within the extremities, and is characterized by a translocation.

Prognosis

In a review of 33 patients (three were younger than 18 years) with low grade fibromyxoid sarcoma, 21 of 33 patients developed a local recurrence after intervals of up to 15 years (median, 3.5 years) and 15 developed metastases up to 45 years (median, 5 years) from diagnosis, most commonly to the lungs and pleura, emphasizing the need for continued follow-up of these patients. Even after metastases occur, the course may be indolent.

In another report, 14 of 73 cases were younger than 18 years of age. In this series with a relatively short follow up (median of 24 months), only 8 of 54 patients with adequate follow up developed local (9%) or distant (6%) recurrence. This report suggests that the behavior of this tumor might be significantly better than previously reported. However, because of the occurrence of late metastases, careful monitoring of these patients is warranted.

The most recent Children's Oncology Group (COG) trial () enrolled 11 patients with this tumor entity. The median age at diagnosis was 13 years and males were more commonly affected. The most common sites were the lower and upper extremity (n = 9) and none of the patients had developed local or distant disease recurrence at a median follow up of 2.7 years.

Treatment

Treatment options for low-grade fibromyxoid sarcoma include the following:

The limited treatment information for low-grade fibromyxoid sarcoma suggest that surgery is the treatment of choice as the tumor is not very chemosensitive. There are little data regarding the use of chemotherapy and/or radiation therapy in this disease. One report suggests that trabectedin may be effective in the treatment of low-grade fibromyxoid sarcoma.

Myxofibrosarcoma

Myxofibrosarcoma is a rare lesion, especially in childhood. It is typically treated with complete surgical resection.

Sclerosing epithelioid fibrosarcoma

Sclerosing epithelioid fibrosarcoma is a rare malignant sarcoma that commonly harbors gene rearrangements and has an aggressive clinical course. It is typically treated with complete surgical excision. Long-term follow-up is recommended because local recurrence and metastases can occur late.

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with infantile fibrosarcoma, inflammatory myofibroblastic tumor, low-grade myofibroblastic tumor, myxoinflammatory fibroblastic sarcoma, solitary fibrous tumor, adult-type fibrosarcoma, low-grade fibromyxoid sarcoma, myxofibrosarcoma, and sclerosing epithelioid fibrosarcoma are eligible for this trial.

Skeletal Muscle Tumors

Rhabdomyosarcoma

Refer to the PDQ summary on Childhood Rhabdomyosarcoma Treatment for more information.

Smooth Muscle Tumors

Leiomyosarcoma

Leiomyosarcoma accounts for 2% of soft tissue sarcoma in patients younger than 20 years (refer to Table 1).

Risk factors

Among 43 children with HIV/AIDS who developed tumors, eight developed Epstein-Barr virus–associated leiomyosarcoma. Survivors of hereditary retinoblastoma have a statistically significant increased risk of developing leiomyosarcoma and 78% of these were diagnosed 30 or more years after the initial diagnosis of retinoblastoma.

Treatment

Treatment options for leiomyosarcoma include the following:

In an open-label study of trabectedin in adult patients with recurrent sarcomas, the best overall response rate (complete remission and partial remission) was seen in patients with leiomyosarcoma (7.5%). The clinical benefit rate (includes stable disease) for leiomyosarcoma was 54%. In another adult study, patients with recurrent liposarcoma and leiomyosarcoma were randomly assigned to receive treatment with either trabectedin or dacarbazine. Patients treated with trabectedin had a 45% reduction in disease progression. There are no data to support the use of trabectedin in pediatric patients.

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with leiomyosarcoma are eligible for this trial.

So-called Fibrohistiocytic Tumors

So-called fibrohistiocytic tumors include the following tumor subtypes:

  • Giant cell tumor of soft tissue.
  • Plexiform fibrohistiocytic tumor.

Plexiform fibrohistiocytic tumor

Plexiform histiocytic tumor is a rare, low- to intermediate-grade tumor that most commonly affects children and young adults. Depending on the series, the median age at presentation ranges from 8 to 14.5 years; however, the tumor has been described in patients as young as 3 months.

Clinical presentation

The tumor commonly arises as a painless mass in the skin or subcutaneous tissue and most often involves the upper extremities, including the fingers, hand, and wrist. There are rare reports of spread to regional lymph nodes or the lungs.

Molecular features

No consistent chromosomal anomalies have been detected but a t(4;15)(q21;q15) translocation has been reported.

Prognosis

Plexiform fibrohistiocytic tumor is an intermediate-grade tumor that rarely metastasizes.

Treatment

Surgery is the treatment of choice but local recurrence has been reported in 12% to 50% of cases.

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with giant cell tumors of soft tissue and plexiform fibrohistiocytic tumor are eligible for this trial.

Tumors of Peripheral Nerves

Ectomesenchymoma

Ectomesenchymoma is a rare nerve sheath tumor that mainly occurs in children. It is a biphenotypic soft tissue sarcoma with both mesenchymal and ectodermal components. Elements similar to rhabdomyosarcoma have been identified.

The German Soft Tissue Sarcoma Group (Cooperative Weichteilsarkon Studiengruppe [CWS]) reported on six patients (ages 0.2–13.5 years) registered over 14 years.[] The tumors were located in various sites including the extremities, abdomen, and orbit. All six patients were treated with surgery and chemotherapy directed at rhabdomyosarcoma. Two patients received radiation therapy. Three patients recurred with rhabdomyosarcoma features. Although data are scant, it appears that the tumor may respond to chemotherapy.

Malignant peripheral nerve sheath tumor

Malignant peripheral nerve sheath tumors account for 5% of soft tissue sarcoma in patients younger than 20 years (refer to Table 1).

Risk factors

Malignant peripheral nerve sheath tumor can arise sporadically and in children with type 1 neurofibromatosis (NF1).

Molecular features

Inactivating mutations of have been described in these tumors and are absent in neurofibromas.

Prognosis

Features associated with a favorable prognosis include the following:

  • Smaller tumor size. In a multivariate analysis, only tumor size and nuclear p53 expression were found to be independent predictors of disease-specific survival.
  • Male sex and non-Hispanic white race.
  • No metastasis at presentation. A retrospective review of 140 patients with malignant peripheral nerve sheath tumor from the MD Anderson Cancer Center included children and adolescents. The disease-specific survival at 10 years was 32%. In this series, presence of metastatic disease was associated with a much worse prognosis.
  • Lower stage.
  • Lower histologic grade.
  • Extremity as the primary site.

Features associated with an unfavorable prognosis include the following:

  • High grade.
  • Deep tumor location.
  • Locally advanced stage at diagnosis.
  • Macroscopically incomplete resection (R2).

For patients with localized disease in the MD Anderson Cancer Center study, there was no significant difference in outcome between patients with and without NF1. In other studies, it was not clear whether the absence of NF1 is a favorable prognostic factor as it has been associated with both favorable and unfavorable outcomes. In the French Sarcoma Group study, NF1 was associated with other adverse prognostic features, but was not an independent predictor of poor outcome.

Treatment

Treatment options for malignant peripheral nerve sheath tumor include the following:

Complete surgical removal of the tumor, whenever possible, is the mainstay of treatment.

The role of radiation therapy is difficult to assess, but durable local control of known postoperative microscopic residual tumor is not assured after radiation therapy.

Chemotherapy has achieved objective responses in childhood malignant peripheral nerve sheath tumor. A large retrospective analysis of the German and Italian experience with malignant peripheral nerve sheath tumor reported that 65% of measurable tumors had objective responses to ifosfamide-containing chemotherapy regimens, but the analysis did not conclusively demonstrate improved survival for chemotherapy. This retrospective analysis also noted a trend toward improved outcome with postoperative radiation therapy. A series of 37 young patients with malignant peripheral nerve sheath tumor and NF1 showed that most patients had large invasive tumors that were poorly responsive to chemotherapy; PFS was 19% and 5-year OS was 28%.

Treatment options under clinical evaluation

The following are examples of national and/or institutional clinical trials that are currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with malignant peripheral nerve sheath tumor are eligible for this trial.
  • (Ganetespib and Sirolimus in Patients With Malignant Peripheral Nerve Sheath Tumors): This trial is testing the combination of ganetespib, the heat shock protein inhibitor, and sirolimus, the mammalian target of rapamycin (mTOR) inhibitor, for the treatment of patients with unresectable or metastatic malignant peripheral nerve sheath tumors. Patients with unresectable soft tissue or bone sarcomas are eligible for phase I of the trial. Patients with unresectable malignant peripheral nerve sheath tumors are eligible for phase II of the trial. Eligibility is restricted to patients aged 18 years and older.
  • (A Phase 1 Study of the EZH2 Inhibitor Tazemetostat in Pediatric Subjects With Relapsed or Refractory -Negative Tumors or Synovial Sarcoma): Patients with -negative tumors are eligible for targeted treatment with an EZH2 inhibitor. This is a phase I, open-label, dose-escalation, and dose-expansion study with a twice-daily oral dose of tazemetostat.
  • (Lorvotuzumab Mertansine in Treating Younger Patients with Relapsed or Refractory Wilms Tumor, Rhabdomyosarcoma, Neuroblastoma, Pleuropulmonary Blastoma, Malignant Peripheral Nerve Sheath Tumor, or Synovial Sarcoma): This is a phase II study of IMGN901 (lorvotuzumab mertansine) in children with relapsed or refractory Wilms tumor, rhabdomyosarcoma, neuroblastoma, pleuropulmonary blastoma, malignant peripheral nerve sheath tumor, and synovial sarcoma. This trial is studying the effects of IMGN901, an antibody-drug conjugate that links a potent antimitotic to antibodies that target CD56.

Malignant triton tumor

Malignant triton tumors are a variant of malignant peripheral nerve sheath tumors. They occur most often in patients with neurofibromatosis type I and consist of neurogenic and rhabdomyoblastic components. Malignant triton tumors are high-grade malignancies. They usually occur before age 35 years and are very rare in children (case reports only).

Malignant triton tumors are not usually responsive to chemotherapy and radiation therapy but have been treated with rhabdomyosarcoma therapy.[] (Refer to the PDQ summary on Childhood Rhabdomyosarcoma Treatment for more information.)

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with malignant triton tumor are eligible for this trial.

Pericytic (Perivascular) Tumors

Myopericytoma

Infantile hemangiopericytoma is a subtype of myopericytoma.

Hemangiopericytoma is a highly vascularized tumor of uncertain origin.

Histology

Histologically, hemangiopericytomas are composed of packed round or fusiform cells that are arranged around a complex vasculature, forming many branch-like structures. Hyalinization is often present. Infantile hemangiopericytomas have similar histology but many are multilobular with vasculature outside the tumor mass.

Treatment and outcome

Treatment of infantile hemangiopericytomas includes the following:

In a series of 17 children, the differences in metastatic potential and response to treatment were clearly demonstrated for adult and infantile hemangiopericytomas. Eleven children were older than 1 year. Several of these patients had disease in the lymph nodes or lungs. Six patients with stage II or III disease progressed and died. Three patients with stage I disease survived, although one had recurrence in the lungs. Six patients had infantile hemangiopericytoma, most were greater than stage I (5 of 6). All six patients survived and three had good responses to vincristine, actinomycin, and cyclophosphamide. Hemangiopericytoma in children younger than 1 year seems to have a better prognosis than in children older than 1 year.

Infantile myofibromatosis

This entity is a fibrous tumor of infancy and childhood that most commonly presents in the first 2 years of life. The lesion can present as a single subcutaneous nodule (myofibroma) most commonly involving the head and neck region or lesions can affect multiple skin areas, muscle, and bone (myofibromatosis).

An autosomal dominant form of the disease has been described and it is associated with germline mutations of the gene.

Treatment

These lesions have an excellent prognosis and can regress spontaneously.

About one-third of cases with multicentric involvement will also have visceral involvement, and the prognosis for these patients is poor. The use of combination therapy with vincristine/dactinomycin and vinblastine/methotrexate have proven effective in cases of multicentric disease with visceral involvement and in cases in which the disease has progressed and has threatened the life of the patient (e.g., upper airway obstruction).

Tumors of Uncertain Differentiation

Tumors of uncertain differentiation include the following tumor subtypes:

  • Alveolar soft part sarcoma.
  • Clear cell sarcoma of soft tissue.
  • Desmoplastic small round cell tumor.
  • Epithelioid sarcoma.
  • Extrarenal rhabdoid tumor.
  • Extraskeletal myxoid chondrosarcoma.
  • Neoplasms with perivascular epithelioid cell differentiation (PEComa NOS, malignant)
  • Primitive neuroectodermal tumor (PNET)/extraskeletal Ewing tumor.
  • Synovial sarcoma (NOS, spindle cell, and biphasic varieties).

Alveolar soft part sarcoma

Alveolar soft parts sarcomas account for 1.4% of soft tissue sarcomas in patients younger than 20 years (refer to Table 1).

Clinical presentation

The median age at presentation is 25 years, and alveolar soft part sarcoma most commonly arises in the extremities but can occur in the oral and maxillofacial region. Alveolar soft part sarcoma in children can present with evidence of metastatic disease.

Molecular features

This tumor of uncertain histogenesis is characterized by a consistent chromosomal translocation t(X;17)(p11.2;q25) that fuses the gene with the gene.

Prognosis

Alveolar soft part sarcoma in children may have an indolent course. Patients with alveolar soft part sarcoma may relapse several years after a prolonged period of apparent remission. Because these tumors are rare, all children with alveolar soft part sarcoma should be considered for enrollment in prospective clinical trials.

In a series of 19 treated patients, one group reported a 5-year OS rate of 80%, a 91% OS rate for patients with localized disease, a 100% OS rate for patients with tumors 5 cm or smaller, and a 31% OS rate for patients with tumors larger than 5 cm. In another series of 33 patients, OS was 68% at 5 years from diagnosis and 53% at 10 years from diagnosis. Survival was better for smaller tumors (≤5 cm) and completely resected tumors.[] Delayed metastases to the brain and lung are uncommon.

Treatment

Treatment options for alveolar soft part sarcoma include the following:

The standard approach is complete resection of the primary lesion. If complete excision is not feasible, radiation therapy should be administered. A study from China reported on 18 patients with alveolar soft part sarcoma of the oral and maxillofacial region; 15 patients were younger than 30 years.[] Surgical removal with negative margins was the primary treatment. All patients survived, and only one patient had metastatic disease recurrence.

A series of 51 pediatric patients aged 0 to 21 years with alveolar soft part sarcoma found an OS rate at 10 years of 78% and an EFS rate of about 63%. Patients with localized disease (n = 37) had a 10-year OS of 87%, and the 14 patients with metastases at diagnosis had a 10-year OS of 44%, partly resulting from surgical removal of primary tumor and lung metastases in some patients. Only 3 of 18 patients (17%) with measurable disease had a response to conventional antisarcoma chemotherapy, but two of four patients treated with sunitinib had a partial response.[] There have been sporadic reports of objective responses to interferon-alpha and bevacizumab.

A small retrospective study of nine adult patients with metastatic alveolar soft part sarcoma treated with sunitinib reported partial response in five patients and stable disease in two patients.[] In a phase II trial of cediranib, an inhibitor of all three known vascular epidermal growth factor receptors, 15 of 43 adult patients (35%) with metastatic alveolar soft part sarcoma had a partial response.[] There have been no open trials for patients with metastatic alveolar soft part sarcoma.

Treatment options under clinical evaluation for alveolar soft part sarcoma

The following are examples of national and/or institutional clinical trials that are currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Phase II Study of Cediranib [AZD2171] in Patients With Alveolar Soft Part Sarcoma): A phase II study of cediranib in patients with alveolar soft part sarcoma is being conducted in patients younger than 16 years at the Clinical Center of the National Institutes of Health.
  • (Sunitinib or Cediranib for Alveolar Soft Part Sarcoma): A phase II trial in which patients with metastatic alveolar soft part sarcoma are randomly assigned to either sunitinib or cediranib monotherapy, with crossover at disease progression. Patients aged 16 years and older are eligible. This study is being conducted at the Clinical Center of the National Institutes of Health.

Clear cell sarcoma of soft tissue

Clear cell sarcoma (formerly and inappropriately called malignant melanoma of soft parts) is a rare soft tissue sarcoma that typically involves the deep soft tissues of the extremities. It is also called clear cell sarcoma of tendons and aponeuroses. The tumor often affects adolescents and young adults.

Patients who have small, localized tumors with low mitotic rate and intermediate histologic grade fare best.

Clinical presentation

The tumor most commonly affects the lower extremity, particularly the foot, heel, and ankle. It has a high propensity for nodal dissemination, especially metastases to regional lymph nodes (12%–43%). The tumor typically has an indolent clinical course.

Molecular features

Clear cell sarcoma of soft tissue is characterized by an fusion.

Treatment

Treatment options for clear cell sarcoma of soft tissue include the following:

In a series of 28 pediatric patients reported by the Italian and German Soft Tissue Cooperative Studies, the median age at diagnosis was 14 years and the lower extremity was the most common primary site (50%). Surgery with or without radiotherapy is the treatment of choice and offers the best chance for cure. In this series, 12 of 13 patients with completely resected tumors were cured. For patients with more advanced disease the outcome is poor and chemotherapy is rarely effective.; []

Desmoplastic small round cell tumor

Desmoplastic small round cell tumor is a rare primitive sarcoma.

Clinical presentation

Desmoplastic small round cell tumor most frequently involves the abdomen, pelvis, or tissues around the testes, but it may occur in the kidney. The tumor occurs more commonly in males and may spread to the lungs and elsewhere. Peritoneal and pelvic lesions frequently have widespread peritoneal implants.

In a large, single-institution series of 65 patients, a correlation was made between computed tomography (CT) scans in most patients and positron-emission tomography (PET)/CT scans in 11 patients. PET/CT scans had very few false-negative results and detected metastatic sites missed on conventional CT scans.

Molecular features

Cytogenetic studies of these tumors have demonstrated the recurrent translocation t(11;22)(p13;q12), which has been characterized as a fusion of the and genes. The fusion confirms the diagnosis of desmoplastic small round cell tumor.

Prognosis

The overall prognosis for desmoplastic small round cell tumor remains extremely poor, with reported rates of death at 90%. Greater than 90% tumor resection either at presentation or after preoperative chemotherapy may be a favorable prognostic factor for OS.

Treatment

There is no standard approach to the treatment of desmoplastic small round cell tumor.

Treatment options for desmoplastic small round cell tumor include the following:

Complete surgical resections are rare, and the overall prognosis for desmoplastic small round cell tumor remains extremely poor, with reported rates of death at 90%. Treatment may include chemotherapy, surgery, and radiation therapy. Multiagent chemotherapy analogous to that used for sarcomas has been used, as well as total abdominal radiation therapy.

The Center for International Blood and Marrow Transplant Research (CIBMTR) analyzed patients with desmoplastic small round cell tumor in their registry who received consolidation with high dose chemotherapy and autologous stem cell reconstitution. While this retrospective registry analysis suggested some benefit for this approach, other investigators have abandoned the approach because of excessive toxicity and lack of efficacy.

Epithelioid sarcoma

Epithelioid sarcoma is a rare mesenchymal tumor of uncertain histogenesis which displays multilineage differentiation.

Clinical presentation

Epithelioid sarcoma commonly presents as a slowly growing firm nodule based in the deep soft tissue; the proximal type predominantly affects adults and involves the axial skeleton and proximal sites. The tumor is highly aggressive and has a propensity for lymph node metastases.

Molecular features

Epithelioid sarcoma is characterized by inactivation of the gene, which is present in both conventional and proximal types of epithelioid sarcoma. This abnormality leads to increased dependence on and tumor formation.

Treatment

Treatment options for epithelioid sarcoma include the following

Patients should be carefully evaluated for the presence of involved lymph nodes; suspicious lymph nodes should be biopsied. Surgical removal of primary and recurrent tumor(s) is the most effective treatment.[]

In a review of 30 pediatric patients with epithelioid sarcoma (median age at presentation, 12 years), responses to chemotherapy were reported in 40% of patients using sarcoma-based regimens, and 60% of patients were alive at 5 years after initial diagnosis. A single-institution retrospective review of 20 patients, including children and adults (median age, 27.3 years), found no difference in the probability of recurrence between patients who received chemotherapy and those who did not receive chemotherapy and suggested that radiation therapy may be useful.

Treatment options under clinical evaluation

The following are examples of national and/or institutional clinical trials that are currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (An Open-Label, Multicenter, Phase 1/2 Study of E7438 [EZH2 Histone Methyl Transferase (HMT) Inhibitor] as a Single Agent in Subjects With Advanced Solid Tumors or With B-cell Lymphomas): A phase I/II study using the histone methyl transferase inhibitor EPZ6438 is currently enrolling patients aged 18 years and older.
  • (A Phase 1 Study of the EZH2 Inhibitor Tazemetostat in Pediatric Subjects With Relapsed or Refractory -Negative Tumors or Synovial Sarcoma): Patients with -negative tumors are eligible for targeted treatment with an EZH2 inhibitor. This is a phase I, open-label, dose-escalation, and dose-expansion study with a twice-daily oral dose of tazemetostat.

Extrarenal (extracranial) rhabdoid tumor

Malignant rhabdoid tumors were first described in children with renal tumors in 1981 (refer to the PDQ summary on Wilms Tumor and Other Childhood Kidney Tumors Treatment for more information) and were later found in a variety of extrarenal sites. These tumors are uncommon and highly malignant, especially in children younger than 2 years.

Extrarenal (extracranial) rhabdoid tumors account for 2% of soft tissue sarcoma in patients younger than 20 years (refer to Table 1).

Molecular features

The first sizeable series of 26 children with extrarenal extracranial malignant rhabdoid tumor of soft tissues came from patients enrolled on the Intergroup Rhabdomyosarcoma Studies I through III during a review of pathology material. Only five patients (19%) were alive without disease. Later, investigation of children with atypical teratoid/rhabdoid tumors of the brain, as well as those with renal and extrarenal malignant rhabdoid tumors, found germline and acquired mutations of the gene in all 29 tumors tested. Rhabdoid tumors may be associated with germline mutations of the gene and may be inherited from an apparently unaffected parent. This observation was extended to 32 malignant rhabdoid tumors at all sites in patients whose mean age at diagnosis was 12 months.

Prognosis

In a Surveillance, Epidemiology, and End Results (SEER) study of 229 patients with renal, central nervous system, and extrarenal malignant rhabdoid tumor, patients aged 2 to 18 years, limited extent of tumor, and delivery of radiation therapy were shown to affect the outcome favorably compared with other patients ( < .002 for each comparison). Site of the primary tumor was not prognostically significant. OS at 5 years was 33%.

Treatment

Treatment includes surgical removal when possible, chemotherapy as used for soft tissue sarcomas (but no single regimen is currently accepted as best), and radiation therapy.[]; []

Responses to alisertib have been documented in four patients with central nervous system (CNS) atypical teratoid/rhabdoid tumors. (Refer to the PDQ summary on Childhood Central Nervous System Atypical Teratoid/Rhabdoid Tumor Treatment summary for more information about CNS atypical teratoid/rhabdoid tumors.)

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (A Phase 1 Study of the EZH2 Inhibitor Tazemetostat in Pediatric Subjects With Relapsed or Refractory -Negative Tumors or Synovial Sarcoma): Patients with -negative tumors are eligible for targeted treatment with an EZH2 inhibitor. This is a phase I, open-label, dose-escalation, and dose-expansion study with a twice-daily oral dose of tazemetostat.

Extraskeletal myxoid chondrosarcoma

Extraskeletal myxoid chondrosarcoma is relatively rare among soft tissue sarcomas, representing only 2.3% of all soft tissue sarcoma. It has been reported in children and adolescents.

Molecular features

Extraskeletal myxoid chondrosarcoma is a multinodular neoplasm. The rounded cells are arranged in cords and strands in a chondroitin sulfate myxoid background. Several cytogenetic abnormalities have been identified (refer to Table 2), with the most frequent being the translocation t(9;22)(q22;q12), involving the genes.

Prognosis

The tumor has traditionally been considered of low-grade malignant potential. However, recent reports from large institutions showed that extraskeletal myxoid chondrosarcoma has significant malignant potential, especially if patients are followed for a long time. Patients tend to have slow protracted courses. Nodal involvement has been well described. Local recurrence (57%) and metastatic spread to lungs (26%) have been reported.

Treatment

Treatment options for extraskeletal myxoid chondrosarcoma include the following:

The therapeutic benefit of chemotherapy has not been established. Aggressive local control and resection of metastases led to OS of 87% at 5 years and 63% at 10 years. Tumors were relatively resistant to radiation therapy.

There may be potential genetic targets for small molecules, but these should be studied as part of a clinical trial. In an adult study, six of ten patients who received sunitinib achieved a partial response.

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (A Phase 1 Study of the EZH2 Inhibitor Tazemetostat in Pediatric Subjects With Relapsed or Refractory -Negative Tumors or Synovial Sarcoma): Patients with -negative tumors are eligible for targeted treatment with an EZH2 inhibitor. This is a phase I, open-label, dose-escalation, and dose-expansion study with a twice-daily oral dose of tazemetostat.

Neoplasms with perivascular epithelioid cell differentiation (PEComas)

Risk factors and molecular features

Benign PEComas are common in tuberous sclerosis, an autosomal dominant syndrome that also predisposes to renal cell cancer and brain tumors. Tuberous sclerosis is caused by germline inactivation of either (9q34) or (16p13.3), and the same tumor suppressor genes are inactivated somatically in sporadic PEComas. Inactivation of either gene results in stimulation of the mTOR pathway, providing the basis for the treatment of nonsurgically curable PEComas with mTOR inhibitors. A small proportion of PEComas have rearrangements with fusions involving various genes including and .

Clinical presentation

PEComas occur in various rare gastrointestinal, pulmonary, gynecologic, and genitourinary sites. Soft tissue, visceral, and gynecologic PEComas are more commonly seen in middle-aged female patients and are usually not associated with the tuberous sclerosis complex. The disease course may be indolent.

Prognosis

Most PEComas have a benign clinical course, but malignant behavior has been reported and can be predicted based on the size of the tumor, mitotic rate, and presence of necrosis.

Treatment

Treatment options have not been defined. Treatment may include surgery or observation followed by surgery when the tumor is large.

Clinical activity with mTOR inhibitors, such as sirolimus, in tumors with evidence of activation and loss has been well documented.

Primitive neuroectodermal tumor (PNET)/extraskeletal Ewing tumor

(Refer to the PDQ summary on Ewing Sarcoma Treatment for more information.)

Synovial sarcoma

Synovial sarcoma accounts for 9% of soft tissue sarcomas in patients younger than 20 years (refer to Table 1).

Synovial sarcoma is one of the most common nonrhabdomyosarcomatous soft tissue sarcomas in children and adolescents. In a 1973 to 2005 SEER review, 1,268 patients with synovial sarcoma were identified. Approximately 17% of these patients were children and adolescents and the median age at diagnosis was 34 years.

Histologic classification

Synovial sarcoma can be subclassified as the following types:

  • Synovial sarcoma, NOS.
  • Synovial sarcoma, spindle cell.
  • Synovial sarcoma, biphasic.

Clinical presentation

The most common tumor location is the extremities, followed by trunk and head and neck. Rarely, a synovial sarcoma may arise in the heart or pericardium.

The most common site of metastasis is the lung. The risk of metastases is highly influenced by tumor size; it is estimated that patients with tumors that are larger than 5 cm have a 32-fold risk of developing metastases when compared with other patients.

Diagnostic evaluation

The diagnosis of synovial sarcoma is made by immunohistochemical analysis, ultrastructural findings, and demonstration of the specific chromosomal translocation t(x;18)(p11.2;q11.2). This abnormality is specific for synovial sarcoma and is found in all morphologic subtypes. Synovial sarcoma results in rearrangement of the gene on chromosome 18 with one of the subtypes (1, 2, or 4) of the gene on chromosome X. It is thought that the SYT/SSX18 transcript promotes epigenetic silencing of key tumor suppressor genes.

In one report, reduced nuclear reactivity on immunohistochemical staining was seen in 49 cases of synovial sarcoma, suggesting that this pattern may help distinguish synovial sarcoma from other histologies.

Prognosis

Patients younger than 10 years have more favorable outcomes and clinical features, including extremity primaries, smaller tumors, and localized disease, than do older patients. A meta-analysis also suggested that response to chemotherapy was correlated with improved survival.

The following studies have reported multiple factors associated with unfavorable outcomes:

  • In a retrospective analysis of synovial sarcoma in children and adolescents who were treated in Germany and Italy, tumor size (>5 cm or ≤5 cm in greatest dimension) was an important predictor of EFS. In this analysis, local invasiveness conferred an inferior probability of EFS, but surgical margins were not associated with clinical outcome.
  • In a single-institution retrospective analysis of 111 patients with synovial sarcoma who were younger than 22 years at diagnosis, larger tumor size, greater depth in tissue, greater local invasiveness, and more proximal tumor location were associated with poorer OS.[]
  • A multicenter analysis of 219 children from various treating centers including Germany, SJCRH, Instituto Tumori, and MD Anderson Cancer Center reported an estimated 5-year OS of 80% and EFS rate of 72%. In this analysis, an interaction between tumor size and invasiveness was observed; in multivariate analysis, patients with large or invasive tumors or with Intergroup Rhabdomyosarcoma Study Clinical Group III disease (localized, incompletely resected or with biopsy only) and IV (metastases at diagnosis) had decreased OS. Treatment with radiation therapy was related to improved OS (hazard ratio, 0.4; 95% confidence interval, 0.2–0.7). In Intergroup Rhabdomyosarcoma Study Group III patients, objective response to chemotherapy (18 of 30 [60%]) correlated with improved survival. In adults, factors such as International Union Against Cancer/American Joint Committee on Cancer stage III and stage IVA, tumor necrosis, truncal location, elevated mitotic rate, age, and histologic grade have been associated with a worse prognosis.
  • Expression and genomic index prognostic signatures have been studied in synovial sarcoma. Complex genomic profiles, with greater rearrangement of the genome, are more common in adults than in younger patients with synovial sarcoma and are associated with a higher risk of metastasis.
  • A review of 84 patients with localized synovial sarcoma who had information on fusion status () and histologic grading found no difference in OS according to these criteria. However, for tumor size at diagnosis, the study showed that patients with tumors between 5 cm and 10 cm had a worse prognosis than those with smaller tumors ( = .02), and patients with tumors larger than 10 cm had even worse OS ( = .0003).[]
  • The German CWS group reviewed 27 evaluable patients younger than 21 years with pulmonary metastases among 296 patients with synovial sarcoma. Metastases involved the lungs in all patients. The 5-year EFS rate was 26%, and the OS rate was 30%. The most important prognostic factor at presentation was that the metastases were limited to one lesion in one lung or one lesion in both lungs (a group they termed oligometastatic). Treatment elements associated with superior survival were adequate local therapy of the primary tumor and, if feasible, for the metastases. The use of whole-lung irradiation did not correlate with better outcomes.[]

Survival after relapse is poor (30% at 5 years). Factors associated with outcome after relapse include duration of first remission (> or ≤ 18 months) and lack of a second remission.

Treatment

Treatment options for synovial sarcoma include the following:

Synovial sarcoma appears to be more sensitive to chemotherapy than many other soft tissue sarcomas, and children with synovial sarcoma seem to have a better prognosis when compared with adults. The most commonly used regimens for the treatment of synovial sarcoma incorporate ifosfamide and doxorubicin. Response rates to the ifosfamide and doxorubicin regimen are higher than in other nonrhabdomyosarcomatous soft tissue sarcomas.

Several studies have reported the following chemotherapy-associated treatment findings:

  • Several treatment centers advocate postoperative chemotherapy after resection and radiation therapy of synovial sarcoma in children and young adults.
  • The International Society of Pediatric Oncology-Malignant Mesenchymal Tumors studies showed that select patients (young age, <5 cm resected tumors) with nonmetastatic synovial sarcoma can have excellent outcome in the absence of radiation, but it is still unclear whether that approach obviates an advantage of radiation for local or regional control.
  • A German trial suggested a benefit for postoperative chemotherapy in children with synovial sarcoma.
  • A meta-analysis also suggested that chemotherapy may provide benefit.
  • In the most recent COG study, 129 patients with synovial sarcoma were prospectively treated using a risk-based therapy program (as detailed in the prognosis section), of which 43 were categorized as low risk, 66 as intermediate risk, and 20 as high risk. At a median follow-up of 2.6 years, 3-year EFS for low-, intermediate-, and high-risk groups were 83%, 79%, and 16%, respectively. The use of risk factor–directed therapy accurately predicted outcomes.
  • The European Pediatric Soft Tissue Sarcoma Study Group performed a prospective study of patients younger than 21 years with synovial sarcoma (CCLG-EPSSG-NRSTS-2005 [NCT00334854]).[] Patients were stratified into the following three risks groups and nonrandomly assigned to treatment by risk group:
    • Low-risk patients had Intergroup Rhabdomyosarcoma Study (IRS) group I tumors less than 5 cm in size and nonaxial primary tumors.
    • Intermediate-risk patients had no axial primary tumors and IRS group I tumors greater than 5 cm or IRS group II tumors.
    • High-risk patients included all patients with axial primary sites (head and neck, lung and pleura, trunk, retroperitoneal), IRS group III tumors, or N1 tumors.

    Outcomes for patients treated on the CCLG-EPSSG-NRSTS-2005 trial are described in Table 9.

Treatment options under clinical evaluation

The following are examples of national and/or institutional clinical trials that are currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (A Pilot Study of Genetically Engineered NY-ESO-1 Specific [c259] T Cells in HLA-A2+ Patients With Synovial Sarcoma): Patients with unresectable, metastatic, or recurrent synovial sarcoma undergo apheresis. Cells are shipped to a central laboratory where they undergo NY-ESO-1 transduction, expansion, and cryopreservation. Patients undergo lymphodepletion with fludarabine and cyclophosphamide, followed by an infusion of autologous transfected cells. Eligibility is restricted to patients with HLA type A2+, age older than 4 years, and weight greater than 18 kg.
  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with alveolar soft part sarcoma, clear cell sarcoma of soft tissue, epithelioid sarcoma, extraskeletal myxoid chondrosarcoma, PEComa, and synovial sarcoma are eligible for this trial.
  • (A Phase 1 Study of the EZH2 Inhibitor Tazemetostat in Pediatric Subjects With Relapsed or Refractory -Negative Tumors or Synovial Sarcoma): Patients with -negative tumors are eligible for targeted treatment with an EZH2 inhibitor. This is a phase I, open-label, dose-escalation, and dose-expansion study with a twice-daily oral dose of tazemetostat.
  • (Lorvotuzumab Mertansine in Treating Younger Patients with Relapsed or Refractory Wilms Tumor, Rhabdomyosarcoma, Neuroblastoma, Pleuropulmonary Blastoma, Malignant Peripheral Nerve Sheath Tumor, or Synovial Sarcoma): This is a phase II study of IMGN901 (lorvotuzumab mertansine) in children with relapsed or refractory Wilms tumor, rhabdomyosarcoma, neuroblastoma, pleuropulmonary blastoma, malignant peripheral nerve sheath tumor, and synovial sarcoma. This trial is studying the effects of IMGN901, an antibody-drug conjugate that links a potent antimitotic to antibodies that target CD56.

Undifferentiated/unclassified sarcoma

Patients with undifferentiated soft tissue sarcoma had been eligible for participation in rhabdomyosarcoma trials coordinated by the Intergroup Rhabdomyosarcoma Study Group and the COG from 1972 to 2006. The rationale was the observation that patients with undifferentiated soft tissue sarcoma had similar sites of disease and outcome as those with alveolar rhabdomyosarcoma. Therapeutic trials for adults with soft tissue sarcoma include patients with undifferentiated soft tissue sarcoma and other histologies, which are treated similarly, using ifosfamide and doxorubicin, and sometimes with other chemotherapy agents, surgery, and radiation therapy.

In the COG trial, patients with high-grade undifferentiated sarcoma were treated with an ifosfamide and doxorubicin-based regimen and were treated with rhabdomyosarcoma-directed therapies in previous Intergroup Rhabdomyosarcoma Study Group studies with a 5-year survival estimate for nonmetastatic patients of 72%.[] Currently, these patients are eligible for the COG open trial for patients with nonrhabdomyosarcomatous soft tissue sarcoma.

Undifferentiated pleomorphic sarcoma/malignant fibrous histiocytoma (high-grade)

At one time, malignant fibrous histiocytoma was the single most common histiotype among adults with soft tissue sarcomas. Since it was first recognized in the early 1960s, malignant fibrous histiocytoma has been plagued by controversy in terms of both its histogenesis and its validity as a clinicopathologic entity. The latest WHO classification no longer includes malignant fibrous histiocytoma as a distinct diagnostic category but rather as a subtype of an undifferentiated pleomorphic sarcoma.

This entity accounts for 2% to 6% of all childhood soft tissue sarcomas. These tumors can arise in previously irradiated sites or as a second malignancy in patients with retinoblastoma.

These tumors occur mainly in the second decade of life. In a series of ten patients, the median age was 10 years and the tumor was most commonly located in the extremities. In this series, all tumors were localized and five of nine (for whom follow-up was available) were alive and in first remission. In another series of 17 pediatric patients with malignant fibrous histiocytoma, the median age at diagnosis was 5 years and the extremities were involved in eight cases. All patients with metastatic disease died and two patients experienced a clinical response to a doxorubicin-based regimen.

(Refer to the PDQ summary on Osteosarcoma and Malignant Fibrous Histiocytoma of Bone Treatment for more information about the treatment of malignant fibrous histiocytoma of bone.)

Treatment options under clinical evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Radiation Therapy With or Without Combination Chemotherapy or Pazopanib Hydrochloride Before Surgery in Treating Patients With Newly Diagnosed Nonrhabdomyosarcoma Soft Tissue Sarcomas That Can be Removed by Surgery): This study will first determine the feasibility of adding a tyrosine kinase inhibitor in combination with radiation therapy or chemotherapy (ifosfamide/etoposide) and radiation therapy in pediatric and adult patients newly diagnosed with unresected intermediate-risk and high-risk nonrhabdomyosarcomatous soft tissue sarcoma. Subsequently, this trial will compare the rates of near-complete pathologic response (>90% necrosis) of: 1) preoperative pazopanib plus chemoradiation therapy versus preoperative chemoradiation therapy alone for potentially resectable (>5 cm), grade 3 intermediate-risk to high-risk chemotherapy-sensitive adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma; and 2) pazopanib plus preoperative radiation therapy versus preoperative radiation therapy alone for potentially resectable, intermediate-risk to high-risk adult and pediatric nonrhabdomyosarcomatous soft tissue sarcoma. Patients with undifferentiated epithelial sarcoma, undifferentiated pleomorphic sarcoma, undifferentiated round cell sarcoma, and undifferentiated spindle cell sarcoma are eligible for this trial.

Vascular Tumors

Vascular tumors vary from hemangiomas, which are always considered benign, to angiosarcomas, which are highly malignant. Vascular tumors include the following tumor subtypes:

  • Angiosarcoma of the soft tissue.
  • Epithelioid hemangioendothelioma.

Angiosarcoma of the soft tissue

Incidence

Angiosarcoma is a rare (accounting for 2% of sarcomas), aggressive, vascular tumor that can arise in any part of the body, but is more common in the soft tissue. Angiosarcoma has an estimated incidence of 2 cases per 1 million; in the United States, it annually affects approximately 600 people who are typically aged 60 to 70 years.

Angiosarcomas are extremely rare in children. However, cases have been reported in neonates and toddlers, with presentation of multiple cutaneous lesions and liver lesions, some of which are positive. Most angiosarcomas involve the skin and superficial soft tissue, although the liver, spleen, and lung can be affected; bone is rarely affected.

Risk factors

Established risk factors include vinyl chloride exposure, radiation exposure, and chronic lymphedema from any cause, including Stewart-Treves syndrome.

Pathology and biology

Angiosarcomas are largely aneuploid tumors. The rare cases of angiosarcoma that arise from benign lesions such as hemangiomas have a distinct pathway that needs to be investigated. amplification is seen in radiation-induced angiosarcoma. mutations and amplifications have been seen with a frequency of less than 50%.

Histopathologic diagnosis can be very difficult because there can be areas of varied atypia. The common feature is an irregular network of channels in a dissective pattern along dermal collagen bundles. There is varied cellular shape, size, mitosis, endothelial multilayering, and papillary formation. Epithelioid cells can also be present. Necrosis and hemorrhage are common. Tumors stain for factor VIII, CD31, and CD34. Some liver lesions can mimic infantile hemangiomas and have focal positivity. Nomenclature of these liver lesions has been difficult and confusing with use of terminology from 1971 (e.g., type I hemangioendothelioma: infantile hemangioma; type II hemangioendothelioma: low-grade angiosarcoma; type III hemangioendothelioma: high-grade angiosarcoma).

Treatment of angiosarcoma of the soft tissue

Treatment options for angiosarcoma of the soft tissue include the following:

Localized disease is cured by aggressive surgery. Complete surgical excision appears to be crucial for angiosarcomas and lymphangiosarcomas despite evidence of tumor shrinkage in some patients who were treated with local or systemic therapy. A review of 222 patients (median age, 62 years; range, age 15–90 years) showed an overall disease-specific survival (DSS) rate of 38% at 5 years. Five-year DSS was 44% in 138 patients with localized, resected tumors but only 16% in 43 patients with metastases at diagnosis. Data on liver transplantation for localized angiosarcoma are limited.[]

Multimodal treatment with surgery, systemic chemotherapy, and radiation therapy is used for metastatic disease, although it is rarely curative. Disease control is the objective in metastatic angiosarcoma, with published progression-free survival rates between 3 months and 7 months and a median overall survival (OS) rate of 14 months to 18 months. In both adults and children, 5-year OS rates between 20% and 35% are reported.

In a child diagnosed with angiosarcoma secondary to malignant transformation from infantile hemangioma, response to treatment with bevacizumab, a monoclonal antibody against vascular endothelial growth factor, combined with systemic chemotherapy, has been reported. A report of eight cases of liver angiosarcoma in children highlighted the misuse of the term and the importance of early diagnosis and treatment of these tumors.

Biologic agents that inhibit angiogenesis have shown activity in adults with angiosarcoma.

Treatment options under clinical evaluation for angiosarcoma of the soft tissue

The following are examples of national and/or institutional clinical trials that are currently being conducted. Information about ongoing clinical trials is available from the NCI website.

Current Clinical Trials

Check the list of NCI-supported cancer clinical trials that are now accepting patients with childhood angiosarcoma. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI website.

Epithelioid hemangioendothelioma

Incidence and outcome

This tumor was first described in soft tissue by Weiss and Enzinger in 1982. Epithelioid hemangioendotheliomas can occur at younger ages, but the peak incidence is in the fourth and fifth decades of life. The tumors can have an indolent or very aggressive course, with overall survival of 73% at 5 years. There are case reports of patients with untreated multiple lesions who have a very benign course compared with other patients who have a very aggressive course. Some pathologists have tried to stratify patients to evaluate risks and adjust treatment, but more research is needed.

Pathology and biology

A gene fusion has been found in a large percentage of patients; less commonly, a gene fusion has been reported. These fusions are not directly targetable with current medicines. Monoclonality has been described in multiple liver lesions, suggesting a metastatic process.

Histologically, these lesions are characterized as epithelioid lesions arranged in nests, strands, and trabecular patterns, with infrequent vascular spaces. Features that may be associated with aggressive clinical behavior include cellular atypia, one or more mitoses per 10 high-power fields, an increased proportion of spindled cells, focal necrosis, and metaplastic bone formation.

Clinical presentation and diagnostic evaluation

Common sites of involvement are liver alone (21%), liver plus lung (18%), lung alone (12%), and bone alone (14%). Clinical presentation depends on site of involvement, as follows:

  • Liver: Hepatic nodules have central vascularity on ultrasound, contrast-enhancing lesions by computed tomography, and low T1 signal and moderate T2 signal on magnetic resonance imaging.
  • Lung: Pulmonary epithelioid hemangioendothelioma may be an asymptomatic finding on chest x-ray or be associated with pleuritic pain, hemoptysis, anemia, and fibrosis.
  • Bone: Bone metastasis may be associated with pathologic fracture. On x-rays, they are well-defined osteolytic lesions and can be multiple or solitary.
  • Soft tissue: Thirty percent of soft tissue cases are associated with metastases, and when present, can have a very aggressive course, with limited response to chemotherapy.
  • Skin: Cutaneous lesions can be raised and nodular or can be warm red-brown plaques.

Treatment of epithelioid hemangioendothelioma

Treatment options for epithelioid hemangioendothelioma include the following:

For indolent cases, observation is warranted. For more aggressive cases, multiple medications have been used, including interferon, thalidomide, sorafenib, pazopanib, and sirolimus. The most aggressive cases are treated with angiosarcoma-type chemotherapy. Surgery is used when possible. Liver transplantation has been used with aggressive liver lesions, both with and without metastases.

Treatment options under clinical evaluation for epithelioid hemangioendothelioma

The following are examples of national and/or institutional clinical trials that are currently being conducted. Information about ongoing clinical trials is available from the NCI website.

Current Clinical Trials

Check the list of NCI-supported cancer clinical trials that are now accepting patients with childhood epithelioid hemangioendothelioma. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI website.

Current Clinical Trials

Check the list of NCI-supported cancer clinical trials that are now accepting patients with nonmetastatic childhood soft tissue sarcoma. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI website.

Treatment of Metastatic Childhood Soft Tissue Sarcoma

Standard treatment options for metastatic childhood soft tissue sarcoma include the following:

For treatment options, refer to the individual tumor type sections of the summary.

The prognosis for children with metastatic soft tissue sarcomas is poor, and these children should receive combined treatment with chemotherapy, radiation therapy, and surgical resection of pulmonary metastases. In a prospective randomized trial, chemotherapy with vincristine, dactinomycin, doxorubicin, and cyclophosphamide, with or without dacarbazine, led to tumor responses in one-third of patients with unresectable or metastatic disease. The estimated 4-year survival rate, however, was poor, with fewer than one-third of children surviving.

Pulmonary Metastases

Generally, children with isolated pulmonary metastases should be considered for a surgical procedure in an attempt to resect all gross disease. For patients with multiple or recurrent pulmonary metastases, additional surgical procedures can be performed if the morbidity is deemed acceptable. In a retrospective review, patients with synovial sarcoma and pulmonary metastases for whom it was possible to completely resect all metastatic lung lesions had better survival than did patients for whom it was not possible to achieve complete resections.[] Formal segmentectomy, lobectomy, and mediastinal lymph node dissection are unnecessary.

An alternative approach is focused radiation therapy (fractionated stereotactic radiation therapy), which has been successfully used in adults to control lesions. The estimated 5-year survival rate after thoracotomy for pulmonary metastasectomy has ranged from 10% to 58% in adult studies. Emerging data suggest a similar outcome after the administration of focused radiation therapy.

Treatment of Progressive/Recurrent Childhood Soft Tissue Sarcoma

With the possible exception of infants with infantile fibrosarcoma, the prognosis for patients with recurrent or progressive disease is poor. No prospective trial has been able to prove that enhanced local control of pediatric soft tissue sarcomas will ultimately improve survival. Therefore, treatment should be individualized for the site of recurrence, biologic characteristics of the tumor (e.g., grade, invasiveness, and size), previous therapies, and individual patient considerations.

Treatment options for recurrent or progressive disease include the following:

Resection is the standard treatment for recurrent pediatric nonrhabdomyosarcomatous soft tissue sarcomas. If the patient has not yet received radiation therapy, postoperative radiation should be considered after local excision of the recurrent tumor. Limb-sparing procedures with postoperative brachytherapy have been evaluated in adults but have not been studied extensively in children. For some children with extremity sarcomas who have received previous radiation therapy, amputation may be the only therapeutic option.

Pulmonary metastasectomy may achieve prolonged disease control for some patients. A large, retrospective analysis of patients with recurrent soft tissue sarcoma showed that isolated local relapse had a better prognosis and that resection of pulmonary metastases improved the probability of survival. In 31 children and adolescents younger than 23 years with pulmonary metastases from synovial sarcoma, complete resection of lung metastases appeared to prolong survival when compared with ten other patients who were not considered candidates for metastasectomy.[] All patients with recurrent tumors should be considered for current clinical trials.

Published results of two studies addressed the outcomes for children with relapsed synovial sarcoma. Most patients in one study had distant relapse (29 of 44 patients), while most patients in the second study had local relapse (27 of 37 patients). Distant recurrence was a poor prognostic variable, while tumor resectability at relapse (as manifested by extremity recurrence) was associated with a better outcome in both studies.

Treatment Options Under Clinical Evaluation

The following is an example of a national and/or institutional clinical trial that is currently being conducted. Information about ongoing clinical trials is available from the NCI website.

  • (Pediatric MATCH: Targeted Therapy Directed by Genetic Testing in Treating Pediatric Patients with Relapsed or Refractory Advanced Solid Tumors, Non-Hodgkin Lymphomas, or Histiocytic Disorders): NCI-COG Pediatric Molecular Analysis for Therapeutic Choice (MATCH), referred to as Pediatric MATCH, will match targeted agents with specific molecular changes identified using a next-generation sequencing targeted assay of more than 3,000 different mutations across more than 160 genes in refractory and recurrent solid tumors. Children and adolescents aged 1 to 21 years are eligible for the trial.

    Tumor tissue from progression or recurrence must be available for molecular characterization. Patients with tumors that have molecular variants addressed by treatment arms included in the trial will be offered treatment on Pediatric MATCH. Additional information can be obtained on the ClinicalTrials.gov website for APEC1621 (NCT03155620).

Current Clinical Trials

Check the list of NCI-supported cancer clinical trials that are now accepting patients with recurrent childhood soft tissue sarcoma. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI website.

Changes to This Summary (08/09/2017)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

General Information About Childhood Soft Tissue Sarcoma

Added text to state that germline mutations or deletions of the () gene are associated with an increased risk of developing extrarenal rhabdoid tumors (cited Eaton et al. as reference 11).

Added text about the results of a review of 30 Italian patients with nonrhabdomyosarcomatous soft tissue sarcoma at visceral sites, including survival rates and unfavorable prognostic factors (cited Ferrari et al. as reference 61 and level of evidence 3iiB).

Staging and Grading Systems for Childhood Soft Tissue Sarcoma

Added text to state that the current open trial (ARST1321 [NCT02180867]) uses the Fédération Nationale des Centres de Lutte Contre Le Cancer system to assign histological grade.

Treatment Option Overview for Childhood Soft Tissue Sarcoma

Added text to state that in a randomized study of 182 previously treated adult patients with recurrent liposarcoma, leiomyosarcoma, synovial sarcoma, and other sarcomas, patients with nonadipocytic tumors who were treated with regorafenib had significant improvements in progression-free survival when compared with patients who were treated with placebo (cited Mir et al. as reference 40).

Treatment of Newly Diagnosed Childhood Soft Tissue Sarcoma

Revised text to state that there are very limited data to support the use of trabectedin in pediatric patients (cited Baruchel et al. as reference 15).

The Dermatofibrosarcoma protuberans subsection was extensively revised.

Added Osborne et al. as reference 167.

Added text to state that a report of eight cases of liver angiosarcoma in children highlighted the misuse of the term and the importance of early diagnosis and treatment of these tumors (cited Grassia et al. as reference 248).

Added text about the NCT01532687 trial as a treatment option under clinical evaluation for angiosarcoma of the soft tissue.

Added Stacchiotti et al. as reference 258.

Added Treatment options under clinical evaluation for epithelioid hemangioendothelioma as a new subsection.

Treatment of Progressive/Recurrent Childhood Soft Tissue Sarcoma

Added text to state that one 13-year-old boy and one 14-year-old girl with multiply recurrent synovial sarcoma and lung metastases had responses to pazopanib for 14 and 15 months, respectively (cited Casanova et al. as reference 7 and level of evidence 3iiDi).

Added Treatment Options Under Clinical Evaluation as a new subsection for progressive/recurrent childhood soft tissue sarcoma.

This summary is written and maintained by the PDQ Pediatric Treatment Editorial Board, which is editorially independent of NCI. The summary reflects an independent review of the literature and does not represent a policy statement of NCI or NIH. More information about summary policies and the role of the PDQ Editorial Boards in maintaining the PDQ summaries can be found on the About This PDQ Summary and PDQ® - NCI's Comprehensive Cancer Database pages.

About This PDQ Summary

Purpose of This Summary

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of childhood soft tissue sarcoma. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.

Reviewers and Updates

This summary is reviewed regularly and updated as necessary by the PDQ Pediatric Treatment Editorial Board, which is editorially independent of the National Cancer Institute (NCI). The summary reflects an independent review of the literature and does not represent a policy statement of NCI or the National Institutes of Health (NIH).

Board members review recently published articles each month to determine whether an article should:

  • be discussed at a meeting,
  • be cited with text, or
  • replace or update an existing article that is already cited.

Changes to the summaries are made through a consensus process in which Board members evaluate the strength of the evidence in the published articles and determine how the article should be included in the summary.

The lead reviewers for Childhood Soft Tissue Sarcoma Treatment are:

  • Denise Adams, MD (Children's Hospital Boston)
  • Louis S. Constine, MD (James P. Wilmot Cancer Center at University of Rochester Medical Center)
  • Holcombe Edwin Grier, MD (Dana-Farber Cancer Institute/Boston Children's Hospital)
  • Andrea A. Hayes-Jordan, MD, FACS, FAAP (M.D. Anderson Cancer Center)
  • Paul A. Meyers, MD (Memorial Sloan-Kettering Cancer Center)
  • Thomas A. Olson, MD (AFLAC Cancer Center and Blood Disorders Service of Children's Healthcare of Atlanta - Egleston Campus)
  • Alberto S. Pappo, MD (St. Jude Children's Research Hospital)
  • R Beverly Raney, MD (Consultant)
  • Stephen J. Shochat, MD (St. Jude Children's Research Hospital)

Any comments or questions about the summary content should be submitted to Cancer.gov through the NCI website's Email Us. Do not contact the individual Board Members with questions or comments about the summaries. Board members will not respond to individual inquiries.

Levels of Evidence

Some of the reference citations in this summary are accompanied by a level-of-evidence designation. These designations are intended to help readers assess the strength of the evidence supporting the use of specific interventions or approaches. The PDQ Pediatric Treatment Editorial Board uses a formal evidence ranking system in developing its level-of-evidence designations.

Permission to Use This Summary

PDQ is a registered trademark. Although the content of PDQ documents can be used freely as text, it cannot be identified as an NCI PDQ cancer information summary unless it is presented in its entirety and is regularly updated. However, an author would be permitted to write a sentence such as “NCI’s PDQ cancer information summary about breast cancer prevention states the risks succinctly: [include excerpt from the summary].”

The preferred citation for this PDQ summary is:

PDQ® Pediatric Treatment Editorial Board. PDQ Childhood Soft Tissue Sarcoma Treatment. Bethesda, MD: National Cancer Institute. Updated . Available at: https://www.cancer.gov/types/soft-tissue-sarcoma/hp/child-soft-tissue-treatment-pdq. Accessed . [PMID: 26389361]

Images in this summary are used with permission of the author(s), artist, and/or publisher for use within the PDQ summaries only. Permission to use images outside the context of PDQ information must be obtained from the owner(s) and cannot be granted by the National Cancer Institute. Information about using the illustrations in this summary, along with many other cancer-related images, is available in Visuals Online, a collection of over 2,000 scientific images.

Disclaimer

Based on the strength of the available evidence, treatment options may be described as either “standard” or “under clinical evaluation.” These classifications should not be used as a basis for insurance reimbursement determinations. More information on insurance coverage is available on Cancer.gov on the Managing Cancer Care page.

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