Abstract

Abstract Background IgG4‐sclerosing cholangitis (IgG4‐SC) patients have an increased level of serum IgG4, dense infiltration of IgG4‐positive plasma cells with extensive fibrosis in the bile duct wall, and a good response to steroid therapy. However, it is not easy to distinguish IgG4‐SC from primary sclerosing cholangitis, pancreatic cancer, and cholangiocarcinoma on the basis of cholangiographic findings alone because various cholangiographic features of IgG4‐SC are similar to those of the above progressive or malignant diseases. Methods The Research Committee of IgG4‐related Diseases and the Research Committee of Intractable Diseases of Liver and Biliary Tract in association with the Ministry of Health, Labor and Welfare, Japan and the Japan Biliary Association have set up a working group consisting of researchers specializing in IgG4‐SC, and established the new clinical diagnostic criteria of IgG4‐SC 2012. Results The diagnosis of IgG4‐SC is based on the combination of the following 4 criteria: (1) characteristic biliary imaging findings, (2) elevation of serum IgG4 concentrations, (3) the coexistence of IgG4‐related diseases except those of the biliary tract, and (4) characteristic histopathological features. Furthermore, the effectiveness of steroid therapy is an optional extra diagnostic criterion to confirm accurate diagnosis of IgG4‐SC. Conclusion These diagnostic criteria for IgG4‐SC are useful in practice for general physicians and other nonspecialists.