Prostatic adenocarcinoma with marked neuroendocrine differentiation

A case is presented of prostatic cancer with marked neuroendocrine differentiation. Double‐labeled immunohistochemical staining was performed with prostate‐specific antigen and Chromogranin A. Both antibodies were localized to some of the cancer cells with Paneth cell‐like features. Furthermore, most of the cancer cells were positively stained with luminal cell marker CAM 5.2, suggesting that neuroendocrine cells originated from the prostatic luminal cells.