Nat. Rev. Gastroenterol. Hepatol. doi:10.1038/nrgastro.2015.182 Figure 1 IgG4-related sclerosing cholangitis presenting with a pancreatic mass and biliary stricture Figure 1 | IgG4-related sclerosing cholangitis presenting with a pancreatic mass and biliary stricture. A 55-year-old Asian man with a history of sialadenitis presented with abdominal pain, itching, jaundice and weight loss. a | MRI revealed markedly dilated CBD with abrupt stricturing in the distal CBD and mildly dilated PD (as shown by arrows), b | associated with a mass in the head of the pancreas (dashed outline). ERCP with brushing and intraductal biopsies were non-diagnostic. An EUS revealed a hypoechoic head of the pancreas that was sampled by FNA and also found to be non-diagnostic. The serum IgG4 level was found to be elevated at 242 mg/dl and the patient improved with corticosteroid treatment. c | Due to ongoing liver test abnormalities, a liver biopsy was performed. Within the liver biopsy sample were numerous foci of mild portal inflammation, consisting of an admixture of lymphocytes, plasma cells, neutrophils, and rare eosinophils. Bile duct injury was characterized by variable degrees of epithelial disarray, inflammatory infiltration of the biliary epithelium, and ductular reaction (inset, H&E stain; 20x magnification). An IgG4 immunostain demonstrated up to 15 IgG4-positive cells per high-powered field, predominantly within the portal tracts (IgG4 immunostain; 20x magnification). CBD, common bile duct; ERCP, endoscopic retrograde cholangiopancreatography; EUS, endoscopy ultrasonography; FNA, fine needle aspirate; H&E, haematoxylin and eosin; PD, pancreatic duct. Bowlus, C. L. et al. (2015) Evaluation of indeterminate biliary strictures Nat. Rev. Gastroenterol. Hepatol. doi:10.1038/nrgastro.2015.182