Progression from adenocarcinoma to small cell carcinoma of the prostate during endocrinotherapy: a case report

72歳男.前立腺癌の治療経過中に前立腺小細胞癌が発生した.剖検所見で肝, 肺, 脾, 腎, 骨髄に転移を認めた.前立腺は全て腫瘍で置き換わっており, 膀胱の病巣は前立腺からの連続的な浸潤と考えられた.初発時に認められた腺癌はchromogranin A, NSE染色で陰性であったが, 再発時の小細胞癌には顆粒状に強く陽性に染色された.PSA染色では, 初発時陽性であったが再発時には一部に認められた腺癌成分以外の小細胞癌は陰性であった.転移巣は全て小細胞癌であったA 72-year-old man had undergone surgical castration for metastatic prostate cancer (stage D2, the PSA value was 4, 300 ng/ml) in September, 1997. He was well clinically for 16 months with undetected level of PSA. However, he presented with general malaise and gross hematuria in May, 1999. After admission to our hospital his condition rapidly deteriorated and he died one week later with respiratory failure. Autopsy revealed extensive involvement of the prostate and bladder by solid tumor with multiple metastases in lungs, liver, spleen, kidneys and bone. Histological examination revealed pure small cell carcinoma of the prostate