Immunoglobulin G4-Related Sclerosing Cholangitis: A Review.

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a steroid-responsive biliary manifestation of IgG4-related disease, commonly associated with type I autoimmune pancreatitis and can mimic primary SC or cholangiocarcinoma. Diagnosis relies on the histology, imaging, serology, other-organ involvement, and response to therapy criteria. First-line therapy is corticosteroids; relapsing or refractory disease requires steroid-sparing immunomodulators or B cell-targeted therapy (rituximab).