[Long-time observation of a case of retroperitoneal fibrosis with Klinefelter's syndrome (author's transl)].

The etiology of retroperitoneal fibrosis still is largely unknown. Autoimmunologic mechanisms, traumata, systemic diseases, and drugs have been discussed as possible etiologic factors. The presented case was found to have a Klinefelter's syndrome besides retroperitoneal fibrosis. We do not believe that there is a relation between the two diseases. The retroperitoneal fibrosis of this case responded well to glucocorticosteroid therapy and the severly reduced renal function became normal.