Isolated IgG4 Autoimmune Cholangitis in the Absence of Pancreatitis

The IgG4-related disease is an uncommon immune-mediated condition affecting multiple organ systems concomitantly; however, it is very rare for a patient to have isolated IgG4 autoimmune cholangitis or IgG4-related disease confined to the hepatobiliary system. The majority of cases are associated with pancreatitis and are incidentally discovered in the workup of acute or chronic pancreatitis. When it affects the hepatobiliary system, it develops as inflammatory fibrosclerosing cholangitis, which can mimic other hepatobiliary diseases such as primary sclerosing cholangitis. Herein, we present a case of type 1 IgG4 autoimmune cholangitis in the absence of pancreatitis. Our case is particularly unique because type 1 is the most common type associated with autoimmune pancreatitis; however, our patient had type 1 without any evidence of pancreatic involvement. Additionally, like most cases of isolated IgG4 autoimmune cholangitis, our patient was refractory to standard therapy. This case highlights the clinical significance, rarity and severity of isolated IgG4 autoimmune cholangitis.