Benign ectopic prostatic tissue involving the seminal vesicle in a patient with prostate cancer: recognition and implications for staging.

We report the finding of benign, ectopic prostatic tissue in the seminal vesicle of a 67-year-old man who underwent a radical cystoprostatectomy for transitional cell carcinoma of the bladder and in whom carcinoma of the prostate was incidentally identified. The benign nature of the ectopic prostatic epithelium within the seminal vesicle was confirmed by its morphologic features and by the identification of an intact basal cell layer surrounding the prostatic epithelium. In this patient with prostatic carcinoma, it was essential to distinguish benign prostatic epithelium from adenocarcinoma to assign a correct tumor stage and determine appropriate treatment.