Once a very rare disease in Western countries, although more common in Africa, this is now a feature of AIDS (see AIDS/HIV). Malignant skin tumours develop, originating from blood vessels. The tumours form purple lumps which generally start on the feet and ankles, then spread up the legs and develop on the arm and hands. In AIDS the sarcoma appears in the respiratory tract and gut, and may cause serious bleeding. Radiotherapy normally cures mild cases of Kaposi's sarcoma, but severely affected patients will need anti-cancer drugs to check the tumours’ growth.