MUCINOUS ADENOCARCINOMA OF URINARY-BLADDER TYPE ARISING FROM THE PROSTATIC URETHRA - DISTINCTION FROM MUCINOUS ADENOCARCINOMA OF THE PROSTATE

We describe two cases of mucinous adenocarcinomas in involving and con fined to the prostate and originating from the prostatic urethra. Thes e cases were identical to adenocarcinomas arising within the urinary b ladder and differed from mucinous adenocarcinoma of the prostate. In b oth cases, an in situ adenocarcinoma component was identified in the o verlying prostatic urethra. In one case the In situ adenocarcinoma aro se in a villous adenoma of the urethra. Both cases contained lakes of mucin lined by tall columnar epithelium with varying degrees of cytolo gic atypia, and one case had mucin-positive signet cells. Tn contrast, mucinous adenocarcinomas of the prostate demonstrate tubules and crib riform glands floating within mucin; mucin-positive signet cells are r are. Both tumors were negative immunohistochemically for prostate-spec ific antigen and prostate-specific acid phosphatase and positive for c arcinoembryonic antigen. One case was treated by radical prostatectomy , and the patient was without evidence of disease with short follow-up , Following simple prostatectomy, the other patient did not undergo de finitive therapy for several years, at which point the tumor had progr essed locally to an advanced stage, In terms of therapy, the distincti on between mucinous adenocarcinoma or urinary bladder-type arising in the prostate depicted within the current study and mucinous adenocarci noma of the prostate is significant.