Case Report: Kaposi Sarcoma in Anti-Glomerular Basement Membrane Disease

<ns3:p>Anti-glomerular basement membrane (anti-GBM) disease is a rare and life-threatening autoimmune vasculitis characterized by rapidly progressive glomerulonephritis, with or without pulmonary hemorrhage. Its management requires aggressive immunosuppressive therapy, including corticosteroids, cyclophosphamide, and plasmapheresis. Kaposi sarcoma (KS) is a vascular neoplasm linked to human herpes virus 8 (HHV-8), most frequently seen in HIV-infected or iatrogenically immunosuppressed patients. We report the case of a 39-year-old man with anti-GBM vasculitis who developed cutaneous Kaposi sarcoma two months after initiation of immunosuppressive treatment. HHV-8–positive spindle cell proliferation was confirmed on skin biopsy. HIV testing was negative, and the lesions regressed following the tapering of corticosteroids and withdrawal of cyclophosphamide. This case highlights the importance of considering KS as a differential diagnosis in patients developing skin lesions under immunosuppressive therapy for autoimmune vasculitis.</ns3:p>