Autoimmune sclerosing cholangiopancreatitis with little pancreatic involvements by imaging findings.

Autoimmune pancreatitis is frequently associated with sclerosing cholangitis. A first clue for suspecting a case of autoimmune pancreatitis is enlargement of the pancreas. We encountered several sclerosing cholangitis cases within a short period, which showed no enlargement of the pancreas and in addition, some showed no irregular narrowing on endoscopic retrograde pancreatography, but they should belong to the same category of autoimmune pancreatitis. We report 5 cases and clarified their characteristics. All five cases showed no enlargement of the pancreas. Two cases showed segmental and one case had diffuse narrowing of the main pancreatic duct. The other two cases showed no irregular narrowing of the main pancreatic duct. Two cases were surgically treated. Two cases received steroid therapy. The other case was treated only by endoscopic biliary drainage. Pathological findings of the bile duct in the surgical specimens of two cases showed that there was a severe infiltration of lymphocytes, IgG4-positive plasmacytes and prominent fibrosis compatible with the findings of sclerosing lymphoplasmacytic cholangitis. We should recognize some sclerosing cholangitis cases showed no enlargement of the pancreas and no irregular narrowing of main pancreatic duct. We propose the concept of "autoimmune sclerosing cholangiopancreatitis".