Abstract
Neuroendocrine tumour (NET) of the urinary bladder (UB) is a rare entity and comprises of well-differentiated, small cell and large cell types. Small and large cell NET like that in lung and gastrointestinal tract have an aggressive nature and are considered high-grade disease. Well-differentiated NET has been thought to be localised and having a good prognosis. We report the first case of metastatic well-differentiated NET of the UB. Our case is a 44-year-old man with well-differentiated NET of UB presented with hepatic and peritoneal metastases on initial diagnosis. He was treated with metaiodobenzylguanidine (MIBG) therapy and had a modest survival of 16 months. The primary well-differentiated NETs can present as a metastatic disease with an aggressive nature. MIBG therapy can be considered as a useful option but overall prognosis is poor. Further research is needed for better understanding and better treatment protocol.