Incidental Small Cell Neuroendocrine Carcinoma and High-Grade Dysplasia in an Orthotopic Ileal Neobladder Three Decades Post-cystectomy: A Case Report.

The utilization of a bowel diversion is standard following radical cystectomy for muscle-invasive bladder cancer. Neoplastic transformations are a known long-term complication of intestinal urinary diversions, although uncommon. Most documented tumors are adenocarcinomas, with neuroendocrine tumors present in exceedingly rare instances. To the best of our knowledge, we present the second case of neuroendocrine tumor found in an orthotopic neobladder. We review the workup and treatment as well as our proposed treatment for low- versus high-risk lesions within a neobladder. This case stresses the importance of lifelong, close monitoring of patients with intestinal urinary diversions.