[Periureteral inflammatory pseudotumor: a case report].

A 59-year old female presented with right flank pain and hydronephrosis. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) before admission (August 2001), revealed a periureteral mass measuring 11 cm in length along the right ureter. Since the preoperative image examinations could not exclude a malignancy, she was admitted for surgery. After admission, however, she presented no abnormal findings in laboratory investigations including tumor markers, urinalysis, urine cytology and retrograde pyelography. C-reactive protein was normalized. CT after admission (September 2001), showed spontaneous regression of the mass. We cancelled the operation and decided to carefully watch this lesion by CT. The lesion continued to regress thereafter. Judging from the clinical course, we regard the mass as inflammatory pseudotumor although pathological diagnosis was not performed. The possibility of preserving the urinary tract in this disease is discussed by reviewing the previously reported inflammatory pseudotumor of the upper urinary tract.