[Case report of inflammatory pseudotumor that occurred at the ureteropelvic junction].

A 60-year-old woman underwent detailed examinations for hepatic disorders and pancreatic tumor at the Department of Internal Medicine. A tumor mass in her left renal pelvis and a thickened wall in her left ureter were observed on computed tomography (CT) and magnetic resonance imaging (MRI) images. Retrograde ureteropyelography and drip infusion pyelography images showed a stenosis in 1 vertebral body from the left ureteropelvic junction. Urinary cytology finding was class III-a; however, malignancy could not be disregarded. Since the patient continued to experience severe dorsal pain, a left nephroureterectomy was subsequently performed at the patient's request. Pathological tests showed no malignant findings, and based on the chronic pyelonephritis, we diagnosed her condition as an inflammatory pseudotumor. Not many inflammatory pseudotumors are found in the urinary tract, and even fewer are manifest in the renal pelvis and ureter. Although inflammatory pseudotumors are generally benign, cases of repeated local recurrence exist. Therefore, a meticulous follow-up observation is required.