Stage III AIDS-related lymphoma is divided into stages III, IIIE, IIIS, and IIIS+E. In stage III, cancer is found in lymph node groups on both sides of the diaphragm (the muscle below the lungs and heart that separates the chest from the abdomen). In stage IIIE, cancer is found in lymph node groups on both sides of the diaphragm and in one area of an organ or tissue that is not part of the lymph system. In stage IIIS, cancer is found in lymph node groups on both sides of the diaphragm and in the spleen. In stage IIIS+E, cancer is found in lymph node groups on both sides of the diaphragm, in the spleen, and in one area of an organ or tissue that is not part of the lymph system.