Hemangiosarcoma is a malignant rare, rapidly growing, highly invasive variety of
cancer. It is a blood-fed sarcoma; that is, blood vessels grow directly into the tumor and it is typically filled with blood.
A frequent cause of death is the rupturing of this tumor, causing the victim to rapidly bleed to death.
Also known as malignant hemangiothelioma or angiosarcoma, is a very aggressive, high-grade soft tissue cancer of
vascular tissue with the skin, heart and spleen the most common areas affected. Dermal (skin) hemangiosarcomas are less aggressive
than visceral tumors with lower metastatic potential and longer survival times. Visceral (internal) tumors are highly malignant
tumors with a poor prognosis. This highly malignant cancer originates in the lining of the blood vessels, spreads rapidly,
causing tumors almost anywhere in the body. Insidiously, it attempts to build its own blood vessel network, making blood-blister-like
formations which disrupt normal organ function. A common form of cancer in dogs, hemangiosarcoma affects mostly older, large
breed dogs although all dogs, including young, can be affected. Males tend to have a higher rate of diagnosis than females,
with German Shepards and Golden Retrievers more affected than other breeds. This cancer has not been reported in large numbers
in Bichons, though it has occurred.
Dermal (skin) hemangiosarcoma often appears as a rosy red or purple to black
growth on the skin, which may be raised. Associated with sun exposure, this form of tumor tends to appear on non-haired or
sparsely haired areas like the abdomen. Dogs with short white-haired fur (such as Dalmatians, Whippetts, Italian Greyhounds,
Bull terriers) are prone to this tumor development. Although solar-induced canine dermal hemangiosarcomas generally do not
have as aggressive biologic behavior as visceral tumors and can be controlled with topical chemotherapy as needed, numerous
lesions may continue to appear over a period of several years. Because 30% of all dogs with dermal hemangiosarcoma develop
metastatic disease, it is important to remove the growths promptly.