Kaposi's sarcoma: a light and electron microscopic study.

A patient with diabetes mellitus who developed the typical classic lesions of Kaposi's sarcoma is described. Our patient presented with a reddish-purple papulonodular lesion on the right foot of five months' duration. A skin biopsy specimen showed a proliferation of spindle cells forming numerous vascular slits and a diffuse extravasation of erythrocytes. The patient's sera was negative for human immunodeficiency virus (HIV) antibodies and cytomegalovirus (CMV) antibodies. Ultrastructural examination demonstrated fibroblast-like spindle cells phagocytosing and digesting red blood cells to form vascular spaces. The patient died, due to gastrointestinal hemorrhage, and the autopsy revealed an extensive visceral involvement of Kaposi's sarcoma.