[Spontaneous urinary extravasation from the renal pelvis associated with ureteral fibroepithelial polyp: report of a case].

A 26-year-old woman presented with a colicky right flank pain. Retrograde pyelogram showed extravasation of the contrast medium from the right renal pelvis and a filling defect in the right ureter 4.5 cm proximal to the ureteral orifice. Urinary cytology was negative for malignancy. A partial ureterectomy with a vesicoureteroneostomy was performed. Gross inspection of the resected distal ureter revealed a 3-mm polyp with a grayish-white smooth surface as well as a ureteral stenosis of 2 cm in length just distal to the polyp. Pathological diagnosis was a fibroepithelial polyp. In our case, urinary extravasation probably resulted from an impacted polyp in the stenotic ureter.