Abstract
The pathological differences between immunogloblinG4-related sclerosing cholangitis (IgG4-SC) and primary sclerosing cholangitis (PSC) have recently been elucidated. However, it is still difficult to make a differential diagnosis between IgG4-SC and hilar cholangiocarcinoma. We report a case of IgG4-SC with normal serum levels of IgG4 and without pancreatic lesions,resulting in a diagnosis of hilar cholangiocarcinoma. A 69-year-old woman who complained of general fatigue was found to have dilatation of the right hepatic duct on abdominal computed tomography (CT). A limited stricture of the hilar bile duct was found by endoscopic retrograde cholangiography (ERC), drip-infusion intravenous cholangiography (DIC-CT) and magnetic resonance cholangiopancreticography (MRCP). Although results of brushing cytology revealed class II, normal levels of IgG4 and negative anti-nuclear antibodies were found in laboratory tests. After hilar cholangiocarcinoma was diagnosed, a right hepatectomy was performed,but the pathological diagnosis given was IgG4-SC based on the postoperative immunohistochemical findings that showed a difference number of plasma cells that were positive for IgG4. This case suggests that it is crucial to make a differential diagnosis of hilar cholangiocarcinoma and atypical IgG4-SC.
