Kaposi's sarcoma and variably acid-fast bacteria in vivo in two homosexual men.

Current epidemiologic data suggest that a possible infectious and contagious microbial agent is responsible for the recent outbreak of Kaposi's sarcoma and the acquired immunodeficiency syndrome affecting young homosexual men. In this histopathologic study, rare foci of acid-fast, and Giemsa-stained coccoid forms, and more rare foci of Gram-variable coccoid forms, were observed within the microscopic skin biopsy specimens from two young homosexual men with Kaposi's sarcoma. These findings, in addition to other previously reported histopathologic findings of similar bacteria in vivo in "typical" cases of Kaposi's sarcoma occurring in elderly Jewish men, suggest that bacteria may be implicated in the pathogenesis of Kaposi's sarcoma.