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Understanding Your Melanoma Pathology Report...

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Suzanne McGettigan, MSN, CRNP
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 9, 2008

Definition of terms

• Cellular Description (the type of melanoma):
  • Superficial Spreading Melanoma
  • Nodular Melanoma
  • Acral Lentiginous
  • Lentigo Melanoma
  • Other: mucosal melanoma
• Breslow Thickness: depth a melanoma lesion extends below the skin surface, measured in millimeters
• Clark's Level: depth a melanoma lesion extends below the skin surface, based on involved skin layer (the larger the level number, the deeper into the tissue it extends)
  • Clark's Level I—lesion involves the dermis
  • Clark's Level II—lesion involves the papillary dermis
  • Clark's Level III—lesion invades and fills the papillary dermis
  • Clark's Level IV—lesion invades reticular dermis
  • Clark's Level V—lesion invades sub-cutaneous tissue

(Depending upon where the melanoma is located on the body, the millimeters of depth for each Clark level can vary widely, so one person's Clark's III may be 1 mm, while another person's is 2 mm.)

• Radial Growth Phase (RGP): The melanoma lesion is described as either having RGP present or absent. If present, RGP indicates that the melanoma is growing horizontally, or radially, within a single plane of skin layer.
• Vertical Growth Phase (VGP): The melanoma is described as either having VGP present or absent. If present, it is an indication that the melanoma is growing vertically, or deeper, into the tissues.
• Tumor-Infiltrating Lymphocytes (TILs): TILs describes the patient's immune response to the melanoma. When the pathologist examines the melanoma under the microscope, he/she looks for the number of lymphocytes within the lesion. This response, or TILs, is usually described as brisk, non-brisk, or absent, although occasionally can be described as mild or moderate. TILs indicate the immune system's ability to recognize the melanoma cells as abnormal.
• Ulceration: Ulceration is the sloughing of dead tissue. This can sometimes occur in the center of a melanoma lesion. The presence of ulceration may alter the stage classification of a melanoma. Ulceration is thought to reflect rapid tumor growth, leading to the death of cells in the center of the melanoma.
• Regression: Regression is described as being present or absent. If it is present, the extent of regression is identified. Regression describes an area within the melanoma where there is absence of melanocytic growth. When regression is present, the total size of the melanoma is hard to characterize.
• Mitotic Rate: This term describes the frequency of division within the melanoma. Higher mitotic rates are associated with more rapidly dividing cells, and therefore larger lesions with greater potential for metastasis.
• Satellites: Satellite lesions are nodules of tumor/melanoma located more than 0.05 mm from the primary lesion. Satellites are described as being present or absent.
• Blood Vessel/Lymphatic Invasion: Blood vessel invasion, aka angioinvasion, as well as lymphatic invasion are described as being present or absent. If present, it means that the melanoma has invaded the blood or lymph system, respectively.

Other words you may encounter

Types of biopsies

• Shave Biopsy: a superficial area of the lesion is taken off, often with a razor-type blade.
• Punch Biopsy: the removal of a circular area of skin with an instrument known as a punch, which comes in various sizes- sort of like a miniature round cookie cutter.
• Incisional Biopsy: the removal of a portion of the affected tissue, for examination, using a knife.
• Excisional Biopsy: the removal of the entire affected area and often some healthy tissue for examination using a knife.

Necrosis

• the death of tissue; may also indicate the rapidity with which the tumor is growing