Imaging: US and CT

IgG4-related disease(IgG4-RD) is characterized by increased serum levels of IgG4, a lymphoplasmacytic infiltrate composed of IgG4-positive plasma cells, storiform fibrosis, obliterative phlebitis, and mild to moderate eosinophilia[1]. IgG4-related sclerosing cholangitis (IgG4-SC) is a biliary lesion associated with IgG4-RD, which is frequently seen in elderly men, characterized by obstructive jaundice owing to a bile ductstricture and responds well to steroid therapy [2]. Recently, the first clinical diagnostic criteria for IgG4-SC were proposed in Japan [3]. As in the diagnostic items of the 2012 IgG4-SC diagnostic criteria, biliary tractimaging of IgG4-SC reveals diffuse or segmental narrowing of the intrahepatic and/or extrahepatic bile ductassociated with thickening of the bile ductwall [3].