Benign Intrahepatic Bile Duct Stricture Difficult to Differentiate from an Intrahepatic Cholangiocarcinoma

A 76-year-old Japanese man was found to have hypotrophy of the hepatic left lobe, and dilatation of left intrahepatic bile duct incidentally when CT was examined after medical treatment for atrial fibrillation. He had a medical history of laparotomic cholecystectomy for gallstone at 56 years old, and the postoperative course had been uneventful. At admission, no abdominal pain, fever, or jaundice was noted. His blood test showed mild leukocytosis, and serum examination showed high ranges of CRP, and DUPAN-2, with normal ranges of IgG4, pANCA, and anti-mitochondria antibody. PET demonstrated high accumulation of 18F-fluorodeoxyglucose in the left intrahepatic bile duct near the confluent region, which was constricted. Benign intrahepatic bile duct stricture was suspected although the disease is rare. We performed left lobectomy of the liver to distinguish it from cholangiocarcinoma. Pathological features of the left lobe showed atrophy of the liver parenchyma, atrophy of the portal vein, and interstitial fibrosis in Glisson’s sheath, and non-specific inflammatory cell infiltrating the constricted bile duct. Pathologic examination showed no atypical/malignant lesion, and we diagnosed a benign intrahepatic bile duct stricture. The postoperative course was uneventful, and the bile duct constriction did not recur after the left lobectomy.