Sclerosing adenosis of the prostate. Histologic features in needle biopsy specimens.

Sclerosing adenosis of the prostate is a pseudoneoplastic lesion that can mimic prostate cancer. Because the lesion is more common in the transition zone, which is only rarely sampled in needle biopsy, it is uncommon to see examples of this lesion in biopsy specimens. Because sampling of the transition zone of the prostate is likely to become more frequent, practicing surgical pathologists must be aware of the morphologic features of sclerosing adenosis of the prostate in needle biopsy specimens, in order to avoid misinterpretation of sclerosing adenosis of the prostate, a benign lesion, as prostate adenocarcinoma. We report the morphologic findings of sclerosing adenosis of the prostate in 3 needle biopsy specimens from 2 patients diagnosed as having sclerosing adenosis. We found a combination of histologic (mainly a cellular myxoid stroma and a double-cell population of acinar cells) and immunohistochemical features demonstrating a continuous basal cell layer with myoepithelial differentiation to be diagnostic.