Overlap of IgG4-related Sclerosing Cholangitis and Primary Biliary Cirrhosis

We herein present a case of an overlap of immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) and primary biliary cirrhosis (PBC). A 61-year-old man was diagnosed with PBC due to abnormal liver biochemical tests and positivity for serum anti-M2 antibody. However, his response to bezafibrate and ursodeoxycholic acid was insufficient. Five years later, his serum IgG4 level was found to increase. His liver biopsy specimens showed features of nonsuppurative destructive cholangitis in some portal tracts and periductal fibrosis with dense infiltration of IgG4-positive cells in other portal tracts. This case demonstrates that the serum IgG4 level may be worth measuring in patients with PBC refractory to conventional treatment.