Small cell carcinoma of the prostate: an underrecognized entity.

Adenocarcinoma is by far the most commonly diagnosed histologic subtype among prostate malignancies. Historically, there has been little awareness of the rare but lethal small cell carcinoma (SCC) in association with prostate cancer. Within the last decade, however, several reports have documented the existence of a neuroendocrine-like tumor arising from cells in the prostate. There is evidence that the development of poorly-differentiated neuroendocrine cells (similar to those found in oat cell carcinomas of the lung) can be seen in the progression of an initially pure adenocarcinoma, possibly due to the totipotential nature of the basal or reserve cells normally present in the prostatic acini. Although pure SCC is rare, admixtures of adenocarcinoma and small cell components may be more prevalent than previously believed. Since effective treatment of a prostatic tumor, or part of a tumor, with an SCC etiology differs from that of pure adenocarcinoma, early recognition of any histologic or clinical changes in the patient with prostate cancer may alter the course of the disease.