Small-cell carcinoma of prostate.

Small-cell carcinoma of the prostate is rare, but lethal. We report on 2 cases and review another 6 cases reported in the English literature. Microscopically the tumor may be pure small-cell carcinoma like that seen in the lung or may have a mixed pattern of adenocarcinoma with small-cell carcinoma. This tumor most probably arises from the basal or reserve cells of the prostatic acini. The totipotential basal cells have dual capacity for differentiation into adenocarcinoma and small-cell carcinoma.