Adenomatoid metaplasia of prostatic urethra.

Adenomatoid metaplasia, or so-called nephrogenic metaplasia, is an uncommon alteration of urothelium associated with prior trauma and/or chronic infection. Although the majority of reported cases of adenomatoid metaplasia have involved the urinary bladder, two cases of patients in whom the metaplastic changes were present in tissue from prostatic resections are presented. The fact that both patients had undergone prior transurethral resections of the prostate further supports the association between adenomatoid metaplasia and trauma. Confusion of adenomatoid metaplasia with prostatic ductal carcinoma in one of the cases emphasizes the importance of the recognition of this lesion. The distinction of adenomatoid metaplasia from ductal carcinomas and from other benign proliferative lesions in the prostatic urethra is discussed.