Heterotopic gastric mucosa in the hilar bile duct mimicking hilar cholangiocarcinoma: report of a case.

We herein report a case of heterotopic gastric mucosa in the hilar bile duct. An asymptomatic 58-year-old male was noted to have mild liver dysfunction in March 2009 during the follow-up for angina pectoris. Abdominal-enhanced CT revealed wall thickening from the upper common hepatic bile duct to the left hepatic bile duct. Endoscopic retrograde cholangiopancreatography (ERCP) showed stenosis at the junction of the left hepatic bile duct. Although the patient's serum tumor markers were all within the normal ranges, the possibility of malignant disease of the biliary tree could not be ruled out. Left hepatectomy with the caudate lobe and resection of the extrahepatic bile duct were performed. Histopathologically, the resected specimen showed a polypoid lesion measuring 2 × 2 cm in size that projected into the lumen of the left hepatic bile duct. Microscopic examination revealed this polypoid lesion to be composed of mucous glands resembling gastric fundic glands, with parietal and chief cells. We also review eight other reports of heterotopic gastric mucosa in the biliary tree previously published in the English literature.