what causes hemangiosarcoma in dogs?
Overview of Canine Hemangiosarcoma. Hemangiosarcoma is a malignant cancer of the cells that form blood vessels. Because these tumors start in blood vessels, they are frequently filled with blood. Consequently, when a blood-filled tumor ruptures, it can cause problems with internal or external bleeding.
With hemangiosarcoma, the pericardium fills up with blood due to rupture of the tumor. When the tumor occurs in the skin, a mass or lump can usually be felt in or under the skin. The mass may become ulcerated and bleed. When the tumor occurs in a bone, it can cause pain and discomfort.