Mixed neuroendocrine-nonneuroendocrine epithelial neoplasm of muscle invasive bladder cancer: a clinicopathologic case study.

Mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are rare malignant neoplasms that may occur in the bladder with highly aggressive behavior. Because of its worse prognosis, when compared to the pure urothelial carcinoma without the neuroendocrine component, the bladder mixed neuroendocrine-nonneuroendocrine epithelial neoplasm may be considered a distinct clinicopathologic entity. We present a case of mixed neuroendocrine-nonneuroendocrine epithelial neoplasm occurring in the urinary bladder of an elderly female with a personal history of chronic kidney disease, drug-resistant urinary tract infections, and neurogenic bladder. Her presenting symptoms included complaints of abdominal pain, urinary urgency, oliguria, dysuria, and occasional hematuria. Recognition of the clinicopathologic features of these rare aggressive neoplasms is important for accurate early diagnosis, necessitating appropriate therapeutic management.