Seminal vesicle intraepithelial neoplasia versus basal cell hyperplasia in a seminal vesicle

In the examination of >3000 radical prostatectomy specimens and their seminal vesicles (SVs), we came across a unique case of an intraepithelial abnormality in preexisting ducts and acini in the left SV of a 73-yr-old patient with prostatic adenocarcinoma. At low magnification, the epithelial lining was thicker than the surrounding normal ducts with obliteration of the acinar lumen. At high magnification, there were varying degrees of cell stratification. Prostate-specific antigen, prostate-specific acid phosphatase, prostate-specific membrane antigen, prostein (P501S), alpha-methylacyl-CoA racemase, and GATA binding protein 3 (GATA3) were negative; p63, 34betaE12, cytokeratin 5/6, and p53 were positive in cells in basal and suprabasal positions, whereas CA-125 was expressed in the luminal cells. The case shows morphologic and immunohistochemical features similar to those of basal cell hyperplasia of the prostate and is different from the early neoplastic epithelial changes of the SV in the transgenic adenocarcinoma mouse prostate model (ie, SV intraepithelial neoplasia). To the best of our knowledge, there are no previous reports of such a change in a human SV. The clinical significance of this lesion is not known and is overshadowed by the presence of prostate cancer.