ANGIOMA

congenital mass of blood vessels that intrudes into bone or other tissues, causing loss of tissue and, in the case of bone, structural weakening. Angiomas may occur in any bone and are often associated with angiomas of the skin or muscles. Most angiomas remain symptomless throughout life, but they may cause collapse of the vertebrae if they occur in the spine, and hemorrhage is a danger in some positions that expose them to stress. Treatment is usually by irradiation, which is supposed to cause clot formation within the mass of vascular tissue; it is believed the clot will then gradually calcify. Surgery is also done but involves a risk of hemorrhage.