Kaposi's sarcoma

Kaposi's sarcoma (KS) is a "a multicentric, malignant neoplastic vascular proliferation characterized by the development of bluish-red cutaneous nodules, usually on the lower extremities, most often on the toes or feet, and slowly increasing in size and number and spreading to more proximal areas. Kaposi's sarcoma occurs spontaneously in Jewish and Italian males in Europe and the United States. An aggressive variant in young children is endemic in some areas of Africa. A third form occurs in about 0.04% of kidney transplant patients."

Since, in the United States, it was most common in older men, its appearance in a concentration of young men was one of the first clues to AIDS and its immunosuppressive effects. It is prevalent in HIV-positive patients.

Pathology
The tumors have endothelium-lined channels and vascular spaces admixed with variably sized aggregates of spindle-shaped cells, and often remain confined to the skin and subcutaneous tissue, but widespread visceral involvement may occur.