The Definition and Causes of Angiosarcoma
A malignant and rapid growing cancer, angiosarcoma is also highly invasive. The endothelial cells that line the walls of the blood and lymphatic vessels are the location from which the tumors arise.
All blood vessels and lymphatics are lined by endothelial cells; the layer being called the endothelium. The tumor begins as a growth of rapidly proliferating immature cells, but can quickly become cancerous and spread to many other systems.