Low-grade neuroendocrine carcinoma (carcinoid tumor) of the prostate.

A case of primary, prostatic, low-grade neuroendocrine carcinoma (carcinoid tumor) is described. The patient is an 86-year-old man who presented with symptoms of gross hematuria of several days' duration. Physical examination and a bladder biopsy specimen revealed the presence of a primary adenocarcinoma of the bladder with invasion into the muscularis propria. A cystoprostatectomy was performed, which revealed the presence of invasive adenocarcinoma of the bladder. Prostatic sampling demonstrated the presence of a low-grade neuroendocrine carcinoma (carcinoid tumor) and a small focus of well-differentiated conventional adenocarcinoma. Immunohistochemical studies using neuroendocrine markers clearly demarcated the presence of the neuroendocrine tumor. The case presented herein highlights the ubiquitous distribution of neuroendocrine neoplasms along the male genitourinary tract and the presence of 3 separate neoplasms in the genitourinary tract.