[Two cases of idiopathic retroperitoneal fibrosis effectively treated with steroid therapy]

Two cases of idiopathic retroperitoneal fibrosis (IRPF) were reported. The first case, in a 72-year old man, was admitted for hydronephrosis with indistinct origin. Following percutaneous nephrostomy, biopsy of retroperitoneal tissue was performed, and IRPF was diagnosed. The treatment consisted of bilateral ureterolysis, intraabdominal transposition of ureters and oral administration of prednisolone for 3 months. The second case, in a 51-year-old woman, was admitted for the evaluation of severe azotemia. As ovarian carcinoma and its ureteral invasion was suspected, simple hysterectomy and bilateral ovariectomy were performed. Typical histological finding of IRPF was also observed. Oral administration of prednisolone has been continued for two years. Recurrence of IRPF has not been observed in these two cases for over two years.