title: IgG4-related sclerosing cholangitis overlapping with autoimmune hepatitis: Report of a case.
abstract: BACKGROUND
  IgG4-related sclerosing cholangitis (IgG4-SC) is the biliary manifestation of IgG4-related disease (IgG4-RD) but the presence of IgG4-SC in the porta hepatis is difficult to differentiate from hilar cholangiocarcinoma (HCCA). IgG4-related autoimmune hepatitis (IgG4-related AIH) is extremely rare and it is not fully clear whether IgG4-related AIH is a hepatic manifestation of IgG4-RD or a subtype of AIH.
  
  
  METHODS
  We present a rare case of a 52-year-old male who was admitted with obstructive jaundice and itchy skin. He primarily presented a severe bile duct stricture in the porta hepatis and an elevated serum level of carbohydrate antigen 19-9 (CA19-9) mimicking HCCA. The patient underwent a surgical resection of the left hepatic lobular and cholecyst as well as common bile duct with a right hepatico-jejunostomy. He was finally diagnosed as IgG4-SC accompanied with IgG4-related AIH by immunohistochemistry, but he lacked conventional autoantibodies. The patient responded well to steroid therapy and remains healthy with no signs of recurrence at six-month follow-up.
  
  
  CONCLUSIONS
  This is the first case report that hepatic portal IgG4-SC overlapping with IgG4-related AIH without the presence of conventional autoantibodies. Additionally, we suggest that IgG4-RD should be always considered in case of a bile duct stricture in the porta hepatis to avoid unnecessary surgical operation.
authors.affiliation: Department of Hepatic-Biliary-Pancreatic Medicine, First Hospital, Jilin University, Changchun 130021, Jilin Province, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Hepatic-Biliary-Pancreatic Medicine, First Hospital, Jilin University, Changchun 130021, Jilin Province, China.
authors.forename: Li
authors.initials: L
authors.lastname: Sun
authors.affiliation: The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States; Division of Pediatric Surgery, Department of Surgery, The Ohio State University, Columbus, OH 43205, United States.
authors.forename: David R
authors.initials: DR
authors.lastname: Brigstock
authors.affiliation: Department of Hepatic-Biliary-Pancreatic Medicine, First Hospital, Jilin University, Changchun 130021, Jilin Province, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Qi
authors.affiliation: Department of Hepatic-Biliary-Pancreatic Medicine, First Hospital, Jilin University, Changchun 130021, Jilin Province, China. Electronic address: gao_runping@126.com.
authors.forename: Runping
authors.initials: R
authors.lastname: Gao
mesh_terms: D001323:Autoantibodies / Q000276:immunology; D001652:Bile Ducts / Q000000981:diagnostic imaging / Q000276:immunology; D015209:Cholangitis, Sclerosing / Q000150:complications / Q000000981:diagnostic imaging* / Q000276:immunology; D019693:Hepatitis, Autoimmune / Q000150:complications / Q000000981:diagnostic imaging* / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G
keywords: Hilar cholangiocarcinoma; IgG4-related autoimmune hepatitis; IgG4-related disease; IgG4-related sclerosing cholangitis