Case reportIgG4-related sclerosing cholangitis overlapping with autoimmune hepatitis: Report of a case

BackgroundIgG4-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.Case presentationWe 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.ConclusionThis 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.