Rare case of primary bladder Wilm's tumor in a 1-year old boy.

Extrarenal Wilms' tumor (EWRT) is a rare entity, but primary bladder Wilm's tumor is even rarer with only 1 case reported. A 1-year old boy came with chronic urinary retention. Abdominal pelvic CT scan revealed intravesical mass arising from anterior bladder wall extending to the prostate and bladder neck. Initial cystoscopic diagnosis revealed chronic granuloma. We decided to perform partial cystectomy with final pathologic result of bladder Wilms' tumor. EWRT may occur in various organs, but primary bladder Wilms' tumor is extremely rare case.