Autoimmune Hemolytic Anemia Obscured by the Obstructive Jaundice Associated with IgG4-related Sclerosing Cholangitis in a Patient with Type 1 Autoimmune Pancreatitis: A Case Report and Review of the Literature

Type 1 autoimmune pancreatitis (AIP) is a pancreatic manifestation of IgG4-retated disease that is often associated with IgG4-related sclerosing cholangitis (IgG4-SC). Autoimmune hemolytic anemia (AIHA) is an immune-related disease that causes hemolytic anemia. Although type 1 AIP/IgG4-SC and AIHA have a shared etiology as a presumed autoimmune disease, they rarely overlap, and their association has not been clarified. Secondary AIHA might not be diagnosed appropriately because the obstructive jaundice observed in type 1 AIP/IgG4-SC can obscure the presence of hemolytic jaundice. We herein report a case of type 1 AIP/IgG4-SC overlapping with secondary AIHA along with a review of the literature.