MR imaging features of fibroepithelial ureteral polyp in a patient with duplicated upper urinary tract.

We describe the magnetic resonance (MR) imaging features of a rare case of fibroepithelial polyp (FEP) in a duplicated upper urinary tract. The FEP appeared as a T2-hyperintense and T1-isointense filling defect within the dilated lower moiety ureter. Post gadolinium-enhanced images revealed enhancement of the FEP without ureteral wall-thickening or enhancement. Retrograde ureterography confirmed the findings, and the patient underwent ureterotomy and removal of the polyp. Histopathological findings were consistent with an FEP. It may be possible to differentiate FEP from an ureteric carcinoma based on MR imaging features. MR imaging may be useful for preoperative diagnosis of a benign ureteric tumour, and may thus prevent an unnecessary nephroureterectomy.