Canine and Feline Fibrosarcoma and Trauma
Dear OncoLink "Ask The Experts,"
Lili Duda, VMD, Section Editor of the OncoLink Veterinary Oncology Menu, responds:
The short answer is yes--there is a definite link between chronic tissue inflammation and sarcoma formation, including inflammation caused by foreign materials in the body (such as surgical implants and traumatic debris). However, there is typically a very long latency period (i.e., years) between start of the inflammation and the development of the tumor. In addition, although the link is well documented in the medical literature (both human and veterinary) it is considered to be a very uncommon occurrence. The link is particularly well documented in cats, in which trauma to the eyeball has been linked to eventual sarcoma formation in the eyeball. In addition, the phenomenon of vaccine-associated sarcomas in cats it thought to be linked to inflammation caused by certain vaccine components.
CT or MRI scans are recommended to more clearly delineate the extent of tumors, and in particular sarcomas, as the visible mass is often only the "tip of the iceberg" and tendrils of tumor can travel along muscle bellies or blood vessels. They can be helpful in planning the type and extent of surgery and/or radiation therapy that might be needed to successfully treat a tumor.
There is a particular type of fibrosarcoma in dogs called "histologically low grade but clinically high grade" fibrosarcoma. What this means is that the tumor appears to be fairly benign (non-aggressive) under the microscope, but tends to be fairly invasive and fast growing in the patient. This tumor occurs in the maxilla (upper jaw) of dogs, and golden retrievers might be predisposed. Conversely, scar tissue that forms in the presence of lots of inflammation (such as that caused by a traumatic wound in the oral cavity) can look very active and aggressive under the microscope, but is really just scar tissue. Diagnosis in these cases can sometimes be difficult, and is based on a combination of biopsy results, progression of disease, and response to antibiotics/anti-inflammatory medication.