Angiosarcoma is a rare type of cancer that develops in the lining of the blood vessels and lymph vessels. It is an aggressive malignancy that carries a poor prognosis if not detected and treated in early stages. The lymph vessels are part of the immune system and collect bacteria. Angiosarcoma happens when cells in the lining of a blood vessel or lymph vessel develop changes in their DNA, which tell the cells to multiply quickly and keep living when healthy cells would die. The result is a buildup of cancer cells that can grow beyond the blood vessel or lymph vessel and invade and destroy healthy body tissue. In time, cancer cells may break away and spread to other areas of the body.

Risk factors for angiosarcoma include radiation therapy, genetic syndromes, and exposure to some cancer-causing chemicals. Symptoms of angiosarcoma depend on where the cancer is located. A common sign of angiosarcoma is a painless lump or mass in soft tissue of the body that can be large or small and can grow in size over time. The mass may be found under the skin or deep in the muscles or other tissues. If the angiosarcoma is growing deeper in the body, such as in the liver, symptoms may be less obvious. Treatment options for angiosarcoma include surgery, radiation therapy, and chemotherapy. The right option for a patient will depend on where the cancer is located, its size, and if it has spread in the body.