Disseminated cutaneous and visceral Kaposi's sarcoma in a patient with rheumatoid arthritis receiving corticosteroids and tacrolimus.

Kaposi's sarcoma (KS) is a vascular lesion of low-grade malignant potential caused by the complex interactions between geographic, genetic, environmental, and immunological factors. We recently experienced a rare case of KS associated with rheumatoid arthritis in a patient receiving corticosteroids and tacrolimus; the KS demonstrated unusually aggressive clinical behavior. We herein report the details of the clinical course and discuss the possible contribution of corticosteroids and tacrolimus to the development of aggressive KS in the present case.