Sclerosing adenosis of the prostate.

A 76-year-old man with frequency, dysuria, and urinary incontinence underwent a transurethral resection of the prostate. On microscopic examination, three prostatic chips had a proliferation of irregular crowded acini, small nests, and single cells within a cellular stroma, which created an infiltrative pattern that was though by some observers to represent carcinoma. The acini were lined by columnar, and focally, by basal (myoepithelial) cells; the latter were more clearly demonstrated with immunoperoxidase stains for cytokeratin and S100 protein. In our opinion, the lesion represents a rare variant of benign prostatic hyperplasia analogous to sclerosing adenosis of the breast.