Benign polyp with prostatic-type epithelium of the urinary bladder: a case report.

We report a case of benign polyp with prostatic-type epithelium of the urinary bladder. A 58-year-old male presented with gross hematuria. Cystoscopic examination revealed a 2-mm polypoid lesion in the mid trigone. Immunohistochemical demonstration of prostatic acid phosphatase and prostatic specific antigen in the urothelial cells as well as the prostatic-type epithelial cells suggested the histogenesis of this polyp to be metaplasia of the urothelium.