Hemangiopericytoma Carcinoma in Dogs

Hemangiopericytoma carcinoma usually occurs in older dogs.

A hemangiopericytoma is a common tumor of dogs, usually developing in the subcutaneous layer of the skin, on and around the limbs. Hemangiopericytoma carcinoma develops when pericytes associated with blood vessels fail to form useful tissue and instead form tumors because improper cell division has caused chromosome damage.

Definition

Pericytes are cells that do not develop properly. When this happens, hemangiopericytomas can form. A hemangiopericytoma does not spread through the body as cancer normally does. This type of tumor tends to recur at the same site after it is removed. Each time it recurs, it grows back more deeply rooted and is more difficult to remove than the time before. If it is not removed, it will continue to grow over years until it eventually invades a part of the body that does not have any space for a tumor to grow, such as the chest cavity. This can lead to the tumor's becoming inoperable. (see reference 1)

Signs/Symptoms

Dogs with a hemangiopericytoma will have a noticeable growth arising on or around the limbs that appears as a round nodule. Hemangiopericytomas are most common in medium- to large-breed dogs 10 years of age or older.

Diagnosis

A veterinarian may be able to diagnose this condition by testing fluid aspirated from the tumor using a fine needle or through testing the tissue, after a biopsy.

Treatments

Preferred treatment consists of surgically removing the tumor and leaving wide margins, to ensure complete removal. Radiation often follows surgical removal, which in many cases can prolong remission. If the hemangiopericytoma continually recurs, amputation of the affected limb is also an option.

Prognosis

Hemangiopericytomas do not metastasize, but they do have a high rate of recurrence and each time they recur there is a higher degree of infiltration into the surrounding tissues. Dogs whose tumors are completely removed have a better prognosis. If microscopic tendrils of neoplastic cells are left behind, the tumor will recur sooner.

References

• Veterinary Partner: Hemangiopericytoma
• University of Georgia: Hemangiopericytomas of Dogs