Small cell cancer of the prostate.

De novo small cell cancer of the prostate is a rare tumor and has different presentation, behavior, and outcome compared with adenocarcinoma. A 66-year-old man presented with symptoms masquerading as a rectal tumor. Primary symptoms were intermittent constipation and diarrhea without any urinary symptoms. Initial staging showed only 2 large pelvic nodes. Prostate-specific antigen was 4.8 ng/L. A transrectal prostate biopsy confirmed small cell histology. After having no response to hormones and carboplatin-etoposide, a course of palliative radiotherapy, docetaxel chemotherapy, and defunctioning colostomy offered palliation. Liver and lytic bone metastases developed later; the patient died 9 months after the presentation.