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. Methods Retrospective single‐centre study of CKS cases. We compared MSM to heterosexual patients. Then, we divided the patients into two subgroups, those requiring a systemic treatment and the others, and we performed univariate and multivariate analyses to determine aggressiveness of CKS. Results Between 2006 and 2015, seventy‐four patients were included. Mean age at diagnosis was 68.9 years; sex ratio (M/F) was 6.4, and 28% were MSM; MSM patients were younger (P = 0.02), less often originated from endemic areas (P < 0.0001). KS was less severe (P = 0.04), required more often a local treatment than a systemic one (P = 0.03). On multivariate analysis, CD4 T‐cell count > 500/mm3 at baseline was associated with a reduced risk of severe evolution. Conclusion First CKS cohort in low‐endemic zone. We describe a fifth subtype of KS: KS in MSM. The CD4 T‐cell count was found to correlate with prognosis.