A 74-year-old woman visited our hospital for epigastric pain. Blood tests revealed elevated levels of total bilirubin, hepatobiliary enzymes, CEA, and CA19-9. Abdominal contrast-enhanced CT showed well-enhancing wall thickening of the lower bile duct, and a dilated upper bile duct. ERCP showed an irregular stricture of the lower bile duct and biopsy revealed the diagnosis of adenocarcinoma. We diagnosed the patient as having distal bile duct cancer, and subtotal stomach-preserving pancreaticoduodenectomy was performed. Histologically, the tumor was composed of two components, including an adenocarcinoma and a neuroendocrine carcinoma component, and the diagnosis of mixed adenoneuroendocrine carcinoma (MANEC) was made. She was given postoperative adjuvant chemotherapy with CDDP and CPT-11, but the disease relapsed with peritoneal dissemination 19 months after the operation. Analysis of 10 Japanese case reports of resected MANEC of the extrahepatic bile duct revealed that the disease frequently relapses in the liver, carrying a poor prognosis. In treating this disease, it is necessary to take into consideration the clinicopathological features of each case.