Azathioprine. An alternative treatment for recurrent idiopathic retroperitoneal fibrosis.

Ureteral obstruction resulting from idiopathic retroperitoneal fibrosis (IRF) generally requires a surgical approach sometimes associated with the administration of a corticosteroid. Corticosteroids alone have also been used successfully for recurrences of IRF after the surgical procedure; however, their success is not uniform. We treated a patient with IRF and ureteral obstruction who showed a dramatic recurrence soon after treatment with prednisone was discontinued. Azathioprine was then considered as an alternative treatment. A six-week course of azathioprine (150 mg/day) resolved all the biologic signs of inflammation, normalized renal function, and greatly improved ureteral obstruction. We discuss the choice of immunosuppressive drugs in the management of the disease and propose azathioprine treatment for the recurrent forms.