[IGg4 related autoimmune hepatitis].

A 50-year-old man was investigated for painless jaundice. The histologic pattern on the liver biopsy study met the criteria of autoimmune hepatitis. Further clinical and laboratory investigation revealed multi-organ involvement, including Mikulicz's disease of the salivary glands and pancreatic insufficiency. The diagnosis of IgG4-related disease was suggested by a finding of elevated blood levels of IgG4. IgG4-related disease is an inflammatory fibrosing condition characterized by T-cell infiltration of affected organs, presence of IgG4-positive plasma cells, and elevated levels of IgG4 in serum. In the present case, the liver histopathology was compatible with one of several well-defined types of liver involvement in IgG4-related disease. IgG4-related disease may mimic malignant tumors of the biliary tract, pancreas, or liver. Undiagnosed patients may progress to end-stage fibrosis or undergo unnecessary surgery. It is highly important that IgG4-related disease be recognized because it is a treatable condition that responds well to steroids.