Definition of Hemangiopericytoma
Hemangiopericytomas are formed from pericytes associated with blood cells. Pericytes are cells that are non-specific in their function and involve some sort of chromosome abnormality. This abnormality triggers the improper development of the cells, creating the hemangiopericytoma which will continue to grow until removed. Unfortunately, hemangiopericytomas can grow back after being removed, involving deeper tissue. Hemangiopericytoma does not spread through the dog's body the way a typical cancer does. It stays centralized in its original position and continues to grow in that location.
Diagnosing Hemangiopericytoma
Hemangiopericytomas develop in the deepest layer of the skin and the tissue immediately under that skin. Your dog will have a lump that feels solid and is not easily distinguishable from the surrounding tissue. Frequently the skin over the lump will have shed the fur. The veterinarian will feel the lump, pressing on it and the surrounding tissue to identify the various tissues involved with the lump and to determine the characteristics of the lump. From this physical examination the veterinarian can make a tentative diagnosis of hemagiopercytoma. The only way for a definite diagnosis is to take a sample of the tumor's cells and have them analyzed by a pathologist. The cell sample may be taken with a fine gauge needle or a biopsy may be required. Once the sample is collected, it is sent for cytologic examination to determine if abnormal cells are present.
Treatment for Hemangiopericytoma
The recommended treatment for hemangiopericytoma is to remove the lump. If the veterinary surgeon removes the total lump and enough of the surrounding healthy tissue, re-occurrence of the growth is unlikely. If the lump is located in an area where this is not possible, there are two alternatives for treatment. Radiation is the first alternative, providing treatment to the tissue left after the lumpectomy. The other alternative is to amputate the limb affected by the hemangiopericytoma after the recurrence of the growth. If the growth recurs, it will return to the same tissue and will grow more deeply seated and more difficult to remove.
The dog owner may also consider allowing the tumor to continue to grow, as these tumors typically are slow growing. The downside to this alternative is that the tumor will continue to grow, it can be disfiguring as it continues to grow and most likely will become lethal to your dog.
Hemangiopericytomas are typically diagnosed on older dogs. With aggressive surgical and radiation treatment, the growth can be removed and prevented from returning. If these aggressive tactics are followed, it is unlikely, although still possible, that the lump will return. After these procedures, your dog can heal from his surgical wounds or recover from the radiation therapy and return to a normal, active lifestyle.