Angiosarcoma
Angiosarcoma is a cancer of the endothelial cells that line the walls of blood vessels or lymphatic vessels. It primarily affects older adults. Most tumors of visceral blood and lymphatic vessel walls are cancerous. Because these cancers are carried by the blood flow or lymphatic flow, they can more easily metastasize to distant sites, particularly the liver and lungs. It may occur at any site but most commonly involves skin, soft tissue, breast, and liver.
Angiosarcomas show signs of hemorrhage and necrosis. Pathologically, tumor cells show increased nuclear to cytoplasm ratio, nuclear hyperchromasia, nuclear pleomorphism and high mitotic activity.
In humans, angiosarcomas and lymphangiosarcomas of the skin are uncommon. However, recent study has identified ultraviolet light from the sun as being linked to the onset of cutaneous angiosarcoma. Angiosarcoma of the liver, a rare fatal tumor, has been seen in workers intensively exposed to the gas vinyl chloride monomer for prolonged periods while working in polyvinyl chloride polymerization plants. It has also been associated with individuals exposed to arsenic-containing insecticides and Thorotrast. In dogs, hemangiosarcoma is relatively common, with the golden retriever and Labrador retriever at higher risk of the disease than other breeds.
