A case of benign bile duct stricture causing difficulty in differential diagnosis from bile duct carcinoma.

We report a patient with benign bile duct stricture causing difficulty in differential diagnosis from bile duct carcinoma. A 66-year-old woman consulted a local physician because of general fatigue. Blood biochemical tests showed increased levels of biliary tract enzymes. Abdominal ultrasonography (US) revealed tapering and blockage of the midportion of the bile duct and dilation of the intrahepatic bile ducts. Magnetic resonance cholangiopancreatography (MRCP) demonstrated obstruction of the midportion of the bile duct. Later, because a marked increase in biliary tract enzymes and jaundice appeared, percutaneous transhepatic biliary drainage (PTBD) was performed. Post-PTBD cytological examination of bile was negative for cancer. A third biopsy showed slight hyperplasia with no malignant findings. Recholangiography, performed through PTBD, suggested gradual improvement of bile duct stricture, but could not completely exclude the possibility of malignancy; thus, resection of the bile duct including the stricture site was performed, and the resected specimen was submitted for intraoperative frozen section examination. Histopathological diagnosis did not reveal malignant findings. After cholecystectomy and bile duct resection, hepaticojejunostomy (Roux-en-Y) was performed. Because only erosion and desquamation of the mucosal epithelium and mild submucosal inflammatory cell infiltration and fibrosis were observed, chronic cholangitis was diagnosed histopathologically. Surgical resection of the bile duct should be considered for potentially malignant stricture of the bile duct.