A fifth subtype of Kaposi's sarcoma, classic Kaposi's sarcoma in men who have sex with men: a cohort study in Paris.

Background: Classic Kaposi's sarcoma (CKS) occurs predominantly among elderly men and is associated with Kaposi's sarcoma-associated herpesvirus (KSHV). In low-endemic countries, KSHV infects predominantly men having sex with men (MSM).

Objectives: To describe a cohort of classic Kaposi sarcoma in a low-endemic area for KSHV, to highlight the features of CKS in MSM and identify prognostic factors.