My dog has been diagnosed with hemangiopericytoma and has surgery scheduled next week. I am not finding much info about this online. Is this a malignant tumor? Her veterinarian looked and pressed on the lump then told us what our dog had. Was the doctor able to tell what the condition was by the look and feel of the lump? What are the characteristics of it? Thanks.
Hemangiopericytomas are low-grade malignant tumors that arise from connective tissue pericytes. Pericytes are cells that surround arterioles (very small blood vessels that feed into capillaries). These tumors may occur on any part of the body, although they most frequently appear on the limbs over joints. They seem to occur frequently in cocker spaniels, German shepherds, Boxers, Irish setters, Siberian huskies, and mixed breeds. Hemangiopericytoma affects dogs over seven years old. There is no sex predilection.
The tumors arise in the dermis (deepest part of the skin) and in the subcutaneous tissues. Clinically they appear lobulated and firm to palpation, and are not well delineated from normal tissues. Usually the skin over a tumor of this type will have lost hair, and the overlying skin may be ulcerated. Hemangiopericytomas tend to be locally invasive, but grow slowly, and infrequently metastasize (spread) to other parts of the body. They tend to invade overlying skin and underlying fascia and muscle.
These tumors may be provisionally diagnosed by physical examination. However, clinically these tumors may resemble other types of soft tissue sarcomas and lipomas (benign fat tumors), so definitive diagnosis of hemangiopericytoma is made histopathologically. A sample of the tumor's cells is sent to a pathologist for evaluation. The sample may be collected with a fine-needle aspiration technique for cytologic evaluation or by biopsy.
Aggressive surgical removal is the treatment of choice. The majority of tumors can be cured if the disposition of the tumor allows the veterinary surgeon to excise the entire mass along with sufficient surrounding margins of normal tissue. Sometimes amputation becomes necessary if the tumor recurs or if is too extensive. If an extensive tumor is on the trunk or a part of the body that cannot be amputated, then radiation may be used as an adjunct to surgery.
About one out of five tumors will recur after excision. When this occurs, radiation therapy may help reduce the incidence of further recurrence. With radiation the tumor can often be controlled (no growth occurs) if surgery is unsuccessful in eliminating the entire tumor. Doxorubicin, a chemotherapy drug, may be given with hyperthermia therapy as an adjunctive treatment in selected cases.
If your dog does not do well, or if the surgery cannot eliminate the entire tumor, you may wish to discuss with your veterinarian the possibility of consultation with a veterinary oncologist or radiation oncologist.
11/17/00
