angiosarcoma /-särkō″mə/ , a rare, malignant tumor consisting of endothelial and fibroblastic tissue that proliferates and eventually surrounds vascular channels. It begins in the lining of the blood vessels. The condition usually occurs in older persons. Angiosarcoma has been associated with exposure to many foreign materials in the body, such as steel, shrapnel, and plastic. This tumor tends to be aggressive and recurs locally as well as metastasizing. Also called hemangiosarcoma, malignant hemangioendothelioma. Compare angioma.
