[Small cell carcinoma of the prostate effectively treated for relatively long term: a case report].

A 72-year-old Japanese man was referred to a hospital because of urinary retention. Digital rectal examination revealed a stony, hard nodule in the prostate. A high level of serum PSA was not detected. Prostatic biopsy was performed, and pathological examination indicated adenocarcinoma of the prostate. He was referred to our hospital for treatment. Imaging examinations revealed no metastases (T4N0M0), so we re-evaluated the biopsy specimens. Immunohistochemical examination revealed prostatic small cell carcinoma. His levels of neuron-specific enolase (NSE) and pro-gastrin-releasing peptide (Pro-GRP) were high. We treated him with combination chemotherapy comprising irinotecan and cisplatin, and the treatment was effective. After four courses of the chemotherapy, levels of NSE and Pro-GRP had decreased, and the prostatic mass had decreased in size. Needle rebiopsy of the prostate demonstrated no evidence of malignancy. Adjuvant external beam radiation therapy was also performed. The patient iss till alive at 18 month after diagnosis with no evidence of relapse or metastasis of the disease.