Neuroendocrine Tumor of the Hilar Bile Duct.

Neuroendocrine tumors usually develop in the gastrointestinal tract, pancreas, and lung. Therefore, a neuroendocrine tumor of the bile duct is quite rare. We present a 59-year-old-male patient whose preoperative diagnosis was hilar cholangiocarcinoma. One month after embolization of the left branch and anterior branch of the portal vein, he underwent left hepatic trisegmentectomy and extrahepatic bile duct resection. Pathological examination revealed the neuroendocrine tumor in the submucosal layer of the hilar bile duct. Because there was no neuroendocrine tumor in other organs, the tumor was considered a primary neuroendocrine tumor of the hilar bile duct, rather than a liver metastasis from other organs. We also present a review of the English literature regarding neuroendocrine tumors of the bile duct.