Cholangiocarcinoma Masquerading as IgG4-related Sclerosing Cholangitis / 대한췌담도학회지

ABSTRACT

IgG4-related sclerosing cholangitis (IgG4-SC) represents a rare but clinically challenging differential diagnosis in patients with biliary strictures which can be mistaken for cholangiocarcinoma. We present a case of a 73-year-old male presented with abdominal discomfort and weight loss. Biliary images showed long-segment luminal narrowing of extrahepatic bile duct associated with prominent enhanced wall thickening, but luminal patency was preserved. Pancreatic images revealed segmental irregular narrowing of main pancreatic duct without upstream duct dilatation. His liver function tests and CA19-9 level were normal. Putting all findings together, IgG4-SC associated with autoimmune pancreatitis was strongly suspected. However, endobiliary biopsy of extrahepatic bile duct revealed adenocarcinoma which was not resectable due to celiac axis involvement. Because there is an overlap in biliary imaging findings between IgG4-SC and cholangiocarcinoma, biopsy is essential for adequate differential diagnosis. We present a case of cholangiocarcinoma masquerading as IgG4-SC based on clinical and imaging findings.