Iatrogenic Kaposi's Sarcoma: a Retrospective Cohort Study in an Italian Tertiary Care Centre

Kaposi's sarcoma (KS) is a lymphoangioproliferative multicentric disorder. Among its four distinct clinical variants, iatrogenic KS (iKS) typically affects patients who have received immunosuppressant regimens for organ transplants, proliferative disorders, or immune-mediated diseases. The aim of the current study was to examine the characteristics of a cohort of patients with iKS, evaluating the differences in terms of epidemiological and clinical features, management and outcomes between organ transplant recipients (OTR) and patients immunosuppressed for other medical conditions.

This retrospective study included, out of 1389 KS patients, 143 patients suffering from iKS being followed in an Italian tertiary care centre from November 1995 to December 2016. Demographic data, clinical features, previous immunosuppressive therapies, management, and outcomes were recorded for each patient.

We detected iKS in 10.3% of the analysed KS population. The mean age was 71.9 years in non-OTR versus 51.4 years in OTR (P = 0.04). Staging at diagnosis showed a more severe disease in non-OTR than in OTR, with stage IA observed in 33.3% of OTR versus 11.8% of non-OTR (P < 0.001) and stage IVB in 29.1% of non-OTR versus 12.1% of OTR (P = 0.001). Corticosteroids represented the most frequent immunosuppressive drugs at diagnosis in both groups, in conjunction with cyclosporine A in OTR. Immunosuppressant reduction or withdrawal was carried out in 93.9% of OTR versus 63.6% of non-OTR (P < 0.001).

As corticosteroids and cyclosporine A are the most common iKS-inducing drugs, their reduction or withdrawal, wherever possible, is needed. Differences in disease severity at presentation between OTR and non-OTR may interfere with the choice of management strategy and the consequent outcome.