Kaposi's sarcoma: a new staging classification.

Reports of an unusual form of Kaposi's sarcoma in young homosexual men in North America have demonstrated that previous classification systems for this disease are incomplete. We describe the clinical characteristics of 49 homosexual men with Kaposi's sarcoma and propose a new staging for the disease. There appear to be four clinically distinct forms of Kaposi's sarcoma: stage I--the more typical locally indolent lesions occurring predominantly in elderly males in North America and Europe; stage II--a locally invasive and aggressive form seen almost exclusively in equatorial Africa; stage III--a disseminated mucocutaneous form, often with lymph node involvement, seen primarily in African children and North American male homosexuals; and stage IV--a disseminated, mucocutaneous form with visceral involvement also seen in African children and North American male homosexuals. These stages are further subtyped as to the presence or absence of the systemic signs of unexplained fever and/or weight loss. Further longitudinal follow-up of these recently diagnosed cases will hopefully document that this proposed staging system correlates with survival data and is useful in the evaluation of treatment regimens for uniformly defined patient groups.