An AIDS-defining illness consisting of individual cancerous lesions caused by an overgrowth of blood vessels. KS typically appears as pink or purple painless spots or nodules on the surface of the skin or oral cavity. KS also can occur internally, especially in the intestines, lymph nodes and lungs, and in this case is life-threatening. The cancer may spread and also attack the eyes. Up to now, KS has been treated with alpha interferon, radiation therapy (outside the oral cavity) and various systemic and intralesional cancer chemotherapies.