Ureteral fibroepithelial polyp causing urinary obstruction.

Ureteral polyps are rare causes of ureteropelvic junction (UPJ) obstruction, particularly in children. We report a nine year-old boy with UPJ obstruction initially suggestive of an obstructive urinary stone. CT showed intraureteral calcification at the UPJ and hydronephrosis. A retrograde pyelogram showed narrowing at the UPJ and partial obstruction that was found to be a ureteral polyp. This case illustrates a rare cause of UPJ obstruction that should be considered when the imaging findings and presentation are atypical for more common etiologies of ureteral obstruction.