Neuroendocrine tumor of the bile duct diagnosed adenocarcinoma preoperatively: Report of a case

Abstract

Neuroendocrine tumor (NET) of the extrahepatic bile duct is extremely rare. Here we report a case of NET of the extrahepatic bile duct which showed radiological and cytological findings similar to those of bile duct cancer. A 78-year-old man was referred to our hospital for a suspicion of bile duct cancer. Contrast-enhanced CT scan showed a mass with delayed enhancement in the middle bile duct. Cytological examination of samples obtained during ERCP suggested adenocarcinoma. He underwent PPPD under the preoperative diagnosis of extrahepatic bile duct cancer. Pathological examination revealed tumor cells which showed trabecular pattern or rosettes and positive for chromogranin A and synaptophysin by immunohistochemical staining, leading to the postoperative diagnosis of NET of the extrahepatic bile duct.