My dog had a spindle cell tumor removed recently. What is this? Is it cancerous?
The designation spindle cell tumor is commonly used for tumors arising in connective tissues that do not have enough distinguishing features for the pathologist to make a confident, more specific diagnosis of the tumor type. Sarcomas (connective tissue tumors) that are poorly differentiated or very primitive are often referred to as spindle cell tumors. These are a mixed group of malignant tumors that may arise from a number of different cell types, including fat-forming and collagen-forming cells and nerve and smooth muscle cells. Special staining techniques may or may not aid the pathologist in determining the cell of origin.
Although originating from different types of cells, most of these tumors behave similarly. They usually grow relatively rapidly, either locally or regionally, but have only a limited tendency to metastasize (spread) to other parts of the body. The determination of whether a given spindle cell tumor is benign or malignant is based on its biologic behavior in the patient more so than on its microscopic characteristics. Larger, deeper, more rapidly growing tumors with a good blood supply are more likely to be malignant. Small, superficial, slower growing lesions with poor blood supply tend to be benign. However, all spindle cell tumors should be considered potentially malignant.
Aggressive surgical excision is the preferred treatment. Generally, if the entire tumor can be removed, along with a margin of normal tissue in all planes, then cure is possible. If the tumor is located on the trunk or frame it may be difficult to get sufficient margins of healthy tissue. In such cases adjunctive treatment such as radiation therapy may be required. If the tumor is on an extremity amputation may be elected. Chemotherapy does not appear to have an effective role in spindle cell tumor treatment.
Most spindle cell tumors will continue to grow and may ulcerate or even appear to get bigger than the dog. Intervening with surgery is often easier if the mass or tumor is fairly small.
Unfortunately, recurrence is common, so multiple surgeries may be needed.
12/07/00
