Neuroendocrine tumours of the urinary bladder: recent advances.

Small cell carcinoma is the most frequently encountered neuroendocrine tumour (NET) of the urinary bladder, and it may present as either pure or in combination with urothelial carcinoma or other histological subtypes. Large cell neuroendocrine carcinoma is increasingly recognized in this location, but it is not yet fully characterized. Well-differentiated NET and paraganglioma of the bladder are rare neuroendocrine neoplasms. Advances in the molecular characterization of these tumours have enhanced our understanding of their biology and can provide better classification and more accurate risk stratification for clinical decision-making.