Abstract
A 69-year-old man presented with jaundice and appetite loss. Blood analyses showed elevated aminotransferase levels, hyperbilirubinemia, positivity for antinuclear antibody, elevated immunoglobulin (Ig) G4 levels, and negativity for hepatitis virus markers. Additionally, computed tomography revealed a focal enlargement of the pancreatic body and enhancement of the peripheral bile ducts. Liver biopsy showed interface hepatitis, supporting a clinical diagnosis of autoimmune hepatitis (AIH). Immunohistochemistry revealed that IgG4-bearing plasma cells accounted for more than 60% of the IgG-bearing plasma cells in the portal area. Then, we started oral prednisolone therapy. After tapering, serum transaminase levels became elevated again, and we had to adjust the dose. Azathioprine maintenance therapy was necessary to prevent relapse. We herein report a case of IgG4-hepatopathy with a clinical course similar to that of AIH with acute onset.