Endoscopic transpapillary intraductal ultrasonography and biopsy in the diagnosis of IgG4-related sclerosing cholangitis

IgG4-related sclerosing cholangitis (IgG4-SC) is one of the diseases associated with autoimmune pancreatitis. Several cases of IgG4-SC showed no pancreas abnormalities and it was difficult to distinguish cholangiocarcinoma. We aimed to clarify the findings of transpapillary intraductal ultrasonography (IDUS) and bile duct biopsy in the patients with IgG4-SC. We retrospectively evaluated the findings of transpapillary IDUS and biopsy in 23 consecutive patients with IgG4-SC at Nagoya City University Hospital between 2004 and 2008. Eleven patients with cholangiocarcinoma were enrolled as a control group. IDUS findings of circular-symmetric wall thickness, a smooth outer margin, a smooth inner margin and a homogeneous internal echo in the stricture were significantly higher in IgG4-SC than in cholangiocarcinoma (p < 0.01). The wall thickness in IgG4-SC in regions of non-stricture on the cholangiogram was significantly greater than that in cholangiocarcinoma (p < 0.0001). A bile duct wall thickness exceeding 0.8 mm in regions of non-stricture on the cholangiogram was highly suggestive of IgG4-SC (sensitivity 95.0%, specificity 90.9%, accuracy 93.5%). In transpapillary biopsy, lymphoplasmacytic infiltration was observed in 100% (17/17), fibrosis in 82% (14/17), and obliterative phlebitis in 0%. The abundant IgG4-positive plasma cells were observed in 18% (3/17). The IDUS findings were useful for distinction of IgG4-SC from cholangiocarcinoma. Transpapillary biopsy was not useful for direct diagnosis of IgG4-SC even after IgG4 immunostaining, but it did allow distinction of IgG4-SC from cholangiocarcinoma in some cases. IDUS and transpapillary biopsy after endoscopic retrograde cholangiopancreatography can provide further information for precise diagnosis of IgG4-SC.