[A case of retroperitoneal fibrosis responding to steroid therapy].

A 73-year-old man presented with acute renal failure due to bilateral hydronephroses. Urography and CT scan revealed stenosis and medial deviation of the bilateral ureters surrounded by a soft tissue mass at the level of the 4-5th lumber vertebrae. Under a diagnosis of retroperitoneal fibrosis, bilateral nephrostomies were temporarily placed and prednisolone administration was initiated at a dose of 20 mg/day. Ureteral passage markedly improved within 2 weeks in association with a decrease in size of the retroperitoneal soft tissue mass. The steroid therapy was continued for 4 months with decreasing dosing schedule. The patient has been doing well without any signs of recurrence for 3 months after the cessation of the steroid therapy.