Hemangiosarcoma, 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.
Because this type of sarcoma grows from the blood cells, the growths themselves are filled with blood which accounts for dark blue or red coloring of the mass. The skin forms of hemangiosarcoma are classified as either dermal and subcutaneous (also called hypodermal).
This form is associated with sun exposure and thus tends to form on non-haired or sparsely haired skin, such as on the abdomen.
The prognosis is guardedly optimistic if the tumor is limited to outer layer of skin (dermal). However, the tumor often proves fatal if it manages to metastasize deep into the tissue or if it has arisen from a deeper, visceral location.
Boxers, pit bulls, golden retrievers, German shepherds, and dogs between the ages of four and 15 years old are at a higher risk.
The tumors may also change in size due to bleeding inside the growth. The following are symptoms related to hermangiosarcoma in dogs:
Solitary mass or multiple masses on the skin
Nodules on skin are raised, firm, and dark
Nodules are usually not ulcerative
In subcutaneous tissue, masses are firm but soft, and fluctuate underneath
Bruising appearance may be present on these masses