Kaposi Sarcoma

A 32-year-old man who was seropositive for HIV presented with a tender lesion on his right foot of about 3 months' duration. The patient's only medication was zidovudine. His CD4⁺ cell count was 120/µL.

A 4.2-mm, erythematous, exophytic papulonodule was noted on the plantar surface. The lesion was separated from the surrounding skin by a narrow cleft, or so-called moat; the skin adjacent to this cleft was hyperkeratotic. The differential diagnosis included eccrine poroma, bacillary angiomatosis, and deep fungal infection.

Dr Ted Rosen of Houston observed that the lesion's clinical appearance was classic for eccrine poroma-a benign tumor that arises from an eccrine sweat gl and typically is found on the sole. However, because of the unreliable nature of cutaneous morphology associated with HIV infection, the lesion was completely removed and submitted for pathologic confirmation. Histologic evaluation revealed the lesion to be Kaposi sarcoma, a disorder that had not been considered in the differential.

Subsequently, disseminated violaceous papules and plaques that are characteristic of Kaposi sarcoma developed in the patient.