Langerhans cell histiocytosis confined to extrahepatic bile duct causing sclerosing cholangitis in child: a case report

Background Langerhans cell histiocytosis (LCH) is an abnormal accumulation of Langerhans cells in various organs that sometimes induces organ dysfunction. LCH can affect the liver, resulting in sclerosing cholangitis and biliary cirrhosis. However, liver and bile duct involvement is usually observed in the disseminated form of LCH. We herein report a rare case of LCH localized only in the extrahepatic bile duct that resulted in severe liver cirrhosis. Case presentation A 3-year-old boy with elevated liver enzymes, obstructive jaundice, and dilation of the common bile duct was referred to our institution. Contrast-enhanced computed tomography showed atrophy of the right hepatic lobe, relative hypertrophy of the left hepatic lobe, choledocholiths, and biliary debris extensively with biliary duct dilation. Magnetic resonance cholangiopancreatography revealed dilation of the intrahepatic and extrahepatic bile ducts and multiple choleliths in the gallbladder and common bile duct. Laparoscopic cholecystectomy, intraoperative cholangiography, liver biopsy, and gastrointestinal fiberscopy were performed. A liver specimen showed severe biliary cirrhosis due to sclerosing cholangitis. The patient then underwent living-donor liver transplantation because of severe liver cirrhosis 3 months after the first surgery. The common bile duct was not suitable for duct-to-duct anastomosis and was resected because of severe inflammation. Histologic sections of the common bile duct showed histiocytic cell proliferation. Immunohistochemistry revealed histiocytoses that were positive for Langerin, S-100 protein, and CD1a. However, no histiocytic cell proliferation was noted in the liver tissue. The definitive diagnosis was LCH localized to the extrahepatic bile duct. LCH in the extrahepatic bile duct seemed to cause sclerosing cholangitis. The patient was discharged uneventfully 2 months after living-donor liver transplantation. Conclusions LCH localized to the extrahepatic bile duct is extremely rare; however, LCH can still affect the extrahepatic bile ducts on occasion. LCH should be considered as a differential diagnosis if pediatric patients show the presence of sclerosing cholangitis.