Extensive Metastatic Cholangiocarcinoma Associated With IgG4-Related Sclerosing Cholangitis Misdiagnosed as Isolated IgG4-Related Sclerosing Cholangitis: A Case Report and Literature Review.

As cholangiographic features of IgG4-related sclerosing cholangitis (IgG4-SC) resemble those of cholangiocarcinoma, it is highly confusing between the 2 conditions on the basis of cholangiographic findings. This study presents a case of extensive metastatic cholangiocarcinoma with IgG4-SC misdiagnosed as isolated IgG4-SC, and reviews recent studies of the 2 diseases.A 56-year-old man with no family history of malignant tumors or liver diseases presented with recurrent mild abdominal pain and distention for 3 months. Magnetic resonance cholangiopancreatography showed a 3.7 cm nodular lesion with unclear boundary in segment VI of the liver. Serum IgG4 and CA19-9 were slightly elevated. Histopathological examination was consistent with the consensus statement on the pathology of IgG4-SC. IgG4-SC was thus considered. Due to his mild symptoms, glucocorticoid was not given at first. However, 3 months after his first admission, he had more severe abdominal pain and further elevated serum CA19-9. Actually he was found suffering from extensive metastatic cholangiocarcinoma with IgG4-SC by exploratory laparotomy.The present case serves as a reminder that extensive metastatic cholangiocarcinoma with or without IgG4-SC may be misdiagnosed as an isolated IgG4-SC case if one relies solely on elevated serum and tissue IgG4 levels. We emphasize on the importance of repeated core needle biopsy or exploratory laparoscopy/laparotomy before immunosuppressive drugs are given, and on follow-up of imaging findings and serum CA19-9 once immunosuppressive therapy is started.