A Curious Case of Autoimmune Pancreatitis with IgG4-related Sclerosing Cholangitis.

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a novel entity that belongs to the immune-mediated fibroinflammatory class of IgG4-related diseases (IgG4-RD). IgG4-SC is noted to be one of the most frequent manifestations of extra-pancreatic disease among IgG4-RD, which is significantly different from primary SC (PSC) and cholangiocarcinoma (CC) as is evident in the varied approaches to treatment. IgG4-RD includes IgG4-SC and autoimmune pancreatitis (AIP). Herein, we presented a case of IgG4-SC in a patient with obstructive jaundice secondary to AIP. We have also discussed the current recommendations for diagnostic and treatment modalities, with an emphasis on the issues that arise in obtaining a definitive classification of disease.