Immunoglobulin G4-related sclerosing cholangitis: pathologic features and histologic mimics.
Since immunoglobulin G4 (IgG4)-related sclerosing cholangitis was first described in 2004, this condition has been recognized as a distinct entity characterized by unique pathologic features. Affected bile ducts show diffuse wall thickening, which represents transmural sclerosing inflammation composed of a dense lymphoplasmacytic infiltrate and fibrosis arranged at least focally in a storiform pattern. A diffuse IgG4-positive plasma cell infiltrate is demonstrable by immunohistochemistry. More than 90% of patients with IgG4-related sclerosing cholangitis have type 1 autoimmune pancreatitis, the remaining presenting as isolated cholangitis. The diagnosis requires a multidisciplinary approach, in which pathologic examination has a critical role. Tissue diagnosis on biopsy specimens (ie, bile duct biopsy, liver needle biopsies) is important, particularly for patients with isolated cholangitis, given the fact that radiological findings of IgG4-cholangitis are not reliable enough for establishing the diagnosis. Furthermore, serum IgG4 levels can be, albeit mildly, elevated in other biliary disorders. Histologic mimics of IgG4-related sclerosing cholangitis include primary sclerosing cholangitis, follicular cholangitis, and sclerosing cholangitis with granulocytic epithelial lesion, the latter 2 being recently described entities.
Histopathology Section, Institute of Liver Studies, King's College Hospital, Denmark Hill, London, UK. yoh.zen@kcl.ac.uk
Yoh
Y
Zen
Yasuni
Y
Nakanuma
Bernard
B
Portmann
D001327:Autoimmune Diseases / Q000175:diagnosis* / Q000276:immunology / Q000378:metabolism; D001652:Bile Ducts / Q000473:pathology; D001706:Biopsy; D002761:Cholangitis / Q000175:diagnosis; D015209:Cholangitis, Sclerosing / Q000175:diagnosis* / Q000276:immunology / Q000378:metabolism; D003937:Diagnosis, Differential; D006098:Granulocytes / Q000473:pathology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008099:Liver / Q000473:pathology; D010195:Pancreatitis / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D010950:Plasma Cells / Q000378:metabolism / Q000473:pathology
D007074:Immunoglobulin G