Early bile duct cancer in a background of sclerosing cholangitis and autoimmune pancreatitis.

A 59-year-old man presented with recent onset jaundice. Initial laboratory and radiologic findings suggested autoimmune pancreatitis (AIP) with consequent obstructive jaundice. All serologic markers for AIP were, however, normal. To confirm the histologic finding of AIP and exclude the possibility of cancer at the thickened segment of common bile duct, cholangioscopic examination was performed and bile duct cancer was observed. The resected specimen showed typical features of AIP throughout the entire pancreas and early carcinomatous change on a background of abundant IgG4-positive cells in the common bile duct. Although chronic biliary inflammation and cholestasis are among bile duct cancer risk factors, the cause-and-effect relationship between sclerosing cholangitis and bile duct cancer needs to be determined by further study, as between AIP and pancreatic cancer. Importantly, histologic exclusion of malignancy is another essential step in the diagnosis of AIP and sclerosing cholangitis as malignancy may coexist in bile duct as well as in the pancreas.