Kaposi Sarcoma as a Cutaneous Vasculitis Mimic: Diagnosis and Treatment.

Painful, palpable purpura usually indicate underlying vasculitis. We report a case of systemic vasculitis treated with immunosuppression that developed painful, vasculitis-like purpuric lesions that progressed rapidly to fulminant Kaposi sarcoma (KS). These purpuric, tumorous lesions resolved completely following the suspension of immunosuppression; however, without immunosuppression, the underlying autoimmunity recurred. This case highlights the potential for early KS to present as a vasculitis mimic or pseudovasculitis that clinicians should keep in mind when purpuric, vasculitis-like lesions develop in an immunosuppressed patient with vasculitis. It is important to recognize these pseudovasculitis lesions as KS rather than recurrent vasculitis so that immunosuppression can be withdrawn.