Complete regression of iatrogenic Kaposi's sarcoma due to corticosteroid treatment in a patient with tubercular pericarditis. A case report.

We report a case of drug-induced Kaposi's sarcoma (KS) on the sole of the right foot in a 71-year-old man, treated for 6 months with corticosteroid therapy (prednisolone 25 mg/day) for pericardial effusion. After corticosteroid withdrawal, a tuberculin skin test became strongly positive and pericardial effusion was considered to be of tubercular origin. The patient remained constantly HIV negative during 14 months of follow-up. Seven months after continuous antitubercular treatment, the KS nodules regressed spontaneously and finally disappeared. Histological studies confirmed the diagnosis of KS and documented its complete regression. Laboratory investigation confirmed prior exposure to CMV, EBV and HSV and suggested drug-induced immunological suppression. Analysis of the HLA system revealed the positivity of locus DR5, associated with classical KS. This case report underscores the relationship between genetic background, environmental factors, drug-induced immunosuppression and the evolution of this peculiar neoplasm.