[Small cell carcinoma of the prostate successfully treated with combined chemotherapy and radiotherapy: a case report].

A 49-year-old man complained of dysuria and pollakisuria. The prostate was enlarged, and the serum level of prostate specific antigen was within the normal range. Under the diagnosis of benign prostatic hypertrophy, transurethral resection of the prostate was performed. Unexpectedly, histopathological examination of the resected tissues revealed pure small cell carcinoma. The serum level of progastrin-releasing peptide (ProGRP) was slightly elevated. The cancer was clinically diagnosed as stage C. Pelvic radiotherapy combined with chemotherapy using cisplatin (CDDP) and etoposide (VP-16) was started according to the treatment for limited small cell cancer of the lung. After one month, the serum level of ProGRP decreased to the normal range. After four months, the prostate was reduced in size without any findings of metastases on computed tomography, and prostate biopsy revealed no viable cancer cells.