[Prostatic carcinoid and neuroendocrine tumors--a case report].

This paper reports a rare primary prostatic adenocarcinoid tumor confirmed by electron microscopy as well as immunohistochemical method including prostate specific antigen and prostatic acid phosphatase. Electron microscopy showed the presence of neuroendocrine granules in the cytoplasm of some tumor cells and the latter method ruled out the possibility of secondary tumor from other organs. It is noted that prostatic adenocarcinoid tumor is one of the diffuse neuroendocrine system tumors. Although the histogenesis of these tumors is not entirely clear, it is believed to be of multiple origins, and may transform through metaplasia into neoplasm.