Clear cell adenocarcinoma of the urinary bladder within a diverticulum

A rare case of clear cell adenocarcinoma within a bladder diverticulum is presented. A 69-year-old man presented to our institution with gross hematuria. Workup, including computed tomography and cystoscopy, revealed a papillary bladder mass within a bladder diverticulum near the right ureteral orifice. Biopsy of the tumor was performed, and the pathologic examination revealed clear cell adenocarcinoma. He underwent bladder diverticulectomy and remained disease free at 1 year of follow-up. The clinicopathologic characteristics of this entity compared with its most difficult pathologic differential diagnosis, nephrogenic adenoma, are reviewed.