As stated above, 3 tumors are associated with HIV infections—KS, squamous cell carcinoma of the anogenital region, and B-cell lymphoma. Kaposi sarcoma, first described by Moritz Kaposi in 1872,39 is a proliferative disorder of spindle cells arising from lymphatic or vascular endothelium with infiltration of plasma cells and extravasation of red blood cells (Figure 3). Four clinical presentations have been described.40 The classic type occurs in older men of Mediterranean origin, ie, Jews, Italians, and North Africans. The lesions usually occur on the lower extremities and follow an indolent course. The endemic type occurs in sub-Saharan Africans and is associated with a broad range of presentations and severity. I can only speculate whether the African endemic KS is related to immunodeficiency due to HIV or to some other chronic infection. The third type is associated with immunosuppression for organ transplantation, which began to appear in the 1970s.41 Finally, the fourth type is AIDS-associated KS. When I left San Francisco in the summer of 1981 to spend 3 years overseas, I had never seen a case of KS. I saw 1 case, a single lesion on the sole of the foot of a Bantu man, during a year's work in South Africa. When I returned to San Francisco in 1984, a second-year medical student could diagnose KS from across the room. The rapid rise in the number of KS cases was dramatic and frightening.