IgG4-related sclerosing cholangitis: Not always an obvious entity

Abstract

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a distinct type of cholangitis, currently recognized as a biliary manifestation of IgG4-related disease. We present a case of type 3 IgG4-SC in a patient with normal IgG4 serum levels, surgically treated for suspicion of cholangiocarcinoma. This case highlights that differentiating between isolated IgG4-SC and cholangiocarcinoma can present a challenging diagnostic dilemma.