A Case of Bile Duct Mixed Neuroendocrine-nonendocrine Neoplasm with a Complete Response to Chemoradiotherapy.

The incidence of neuroendocrine carcinomas arising from the bile duct is low, and that of mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) is even lower; therefore, there is no standard treatment for MiNENs. Choosing the appropriate treatment in clinical practice is difficult. We herein report a case of unresectable extrahepatic bile duct MiNEN in a 66-year-old man who received curative chemoradiotherapy and achieved a complete response, remaining recurrence-free for 2.5 years. We consider the findings of this case to be valuable in selecting a treatment strategy for unresectable bile duct MiNENs.