A case of retroperitoneal fibrosis responding to steroid therapy.

A 69-year-old man presented at the hospital with complaints of prolonged stomach pain extending from the week prior. Enhanced computed tomography (CT) revealed a low density area in the retroperitoneal space. A radiologist diagnosed the patient with retroperitoneal fibrosis. One week later, an enhanced CT revealed an exponential increase of the low density area and slight right hydronephrosis. Upon admission, prednisolone administration was initiated at a dose of 40mg/day. The size of the retroperitoneal soft tissue mass decreased gradually. Although the dose of prednisolone was tapered to 5mg, the patient is doing well without any sign of recurrence.