De novo large cell neuroendocrine carcinoma of the prostate gland with pelvic lymph node metastasis: a case report with review of literature

Neuroendocrine (NE) differentiation in prostate carcinomas can be seen in two settings: as a focal finding in conventional acinar adenocarcinoma, identifiable by immunohistochemical staining, or as a primary NE tumor of the prostate gland, such as carcinoid, small cell carcinoma, or large cell NE carcinoma. Of particular interest is the large cell NE carcinoma, which had been previously reported in isolated cases or in limited case series. In this report, we describe a case of a large cell NE carcinoma diagnosed in a 48-year-old man who presented with difficulty in voiding and urine retention. A cystoscopy revealed an enlarged, elongated prostate with an intra-urethral obstructing mass in the prostatic urethra. Subsequently, a transurethral resection of prostate (TURP) was performed at an outside hospital under the clinical diagnosis of benign prostatic hyperplasia (BPH). Microscopic examination of the TURP specimen revealed several foci of low-grade transitional-zone-type adenocarcinoma corresponding to Gleason score 5 (3 + 2), and a focus of high-grade large cell NE carcinoma. Concurrent x-ray computed tomography scans of the chest, abdomen, and pelvis demonstrated an enlarged left pelvic lymph node, which was biopsied and the patient was diagnosed with metastatic large cell NE carcinoma. He subsequently underwent 8 cycles of neoadjuvant chemotherapy with Lupron, a laparoscopic robotic-assisted radical retropubic prostatectomy, and pelvic lymphadenectomy. He died of widely metastatic prostatic carcinoma with leptomeningeal metastases 13 months after radical prostatectomy. Here, we present a rare case of large cell NE carcinoma with a review of the published literature.