noun. a rare malignant neoplasm arising from vascular tissue; usually occurs in the breast and skin and is believed to originate from the endothelial cells of blood vessels.
1. Noun, singular or mass Neoplasia, angiosarcoma and leukemia are cancers associated with lymphocytopenia. 2. Noun, plural According to the National Institutes of Health, vinyl chloride is a known carcinogen linked to angiosarcoma of the liver in humans.