A Case of Primary Bladder Neuroendocrine Carcinoma With Urethral Invasion Following Radical Prostatectomy.

Primary bladder neuroendocrine carcinoma (NEC) is rare and aggressive. We report the first case of bladder NEC with urethral invasion following radical retropubic prostatectomy (RRP) that was successfully managed by multimodal therapy. An 80-year-old man with a history of RRP presented with gross hematuria. Transurethral resection revealed mixed high-grade urothelial carcinoma and NEC; the clinical stage was at least cT1N0M0. After neoadjuvant chemotherapy with gemcitabine-cisplatin and etoposide-cisplatin, robot-assisted radical cystectomy (RARC) with transperineal urethrectomy and ileal conduit diversion was performed. Severe adhesions between the bladder and rectum due to prior RRP were safely dissected using a perineal-first approach aided by magnified robotic three-dimensional visualization. Complete resection was achieved without complications; pathological examination confirmed ypT0N0. No recurrence was observed after 1 year. This case demonstrated that RARC combined with transperineal urethrectomy was a feasible and safe option for bladder NEC after RRP when performed by an experienced urologist.