Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 1 December 2011, last major update November 2011
Copyright: (c) 2002-2011, PathologyOutlines.com, Inc.
● 6% of total IgG; least abundant of IgG subclasses
● IgG4 related sclerosing disease is a syndrome affecting various sites with elevated serum IgG4 and site-related lymphoplasmacytic infiltrates, increased IgG4+ plasma cells and sclerosis
● Common sites are head and neck [eosinophilic angiocentric fibrosis (possibly, Am J Surg Pathol 2011;35:701), idiopathic cervical (neck) fibrosis (Am J Surg Pathol 2010;34:1678), salivary glands (Am J Surg Pathol 2010;34:202)], liver (Mod Pathol 2009;22:1287), lung (Am J Surg Pathol 2009;33:1886, Am J Surg Pathol 2009;33:1450), pancreatobiliary region (sclerosing pancreatitis, N Engl J Med 2001;344:732) and systemic (Am J Surg Pathol 2010;34:1812)
● Other sites: abdominal aortic aneurysms (Am J Surg Pathol 2008;32:197), breast (Am J Surg Pathol 2009;33:1058), CNS (Am J Surg Pathol 2009;33:1249), kidney (Hum Pathol 2011 Aug 31 [Epub ahead of print]), lymph nodes (Am J Surg Pathol 2008;32:671, Mod Pathol 2011 Nov 11 [Epub ahead of print]), ureter (Hum Pathol 2011;42:1178)
● In ocular disease, associated lymphomas have numerous IgG4+ monotypic plasma cells (Am J Surg Pathol 2008;32:1159)
● Cytoplasmic staining
Uses by Pathologists
● Diagnose IgG4 related sclerosing diseases, including some cutaneous pseudolymphomas (Am J Surg Pathol 2009;33:1713), although presence of numerous IgG4+ plasma cells by itself is not specific (Mod Pathol 2011;24:1480)
● Differentiate IgG4 related sclerosing disease (high number and percentage of IgG4+ plasma cells in tissue ) from inflammatory myofibroblastic tumor (low number and percentage, Am J Surg Pathol 2009;33:1330, but see Mod Pathol 2011;24:606) or other lesions (Am J Surg Pathol 2008;32:1770, Hum Pathol 2010;41:643)
Cholangitis explant-IgG4 related
Eye-MALT lymphoma with infiltration by IgG4+ plasma cells
Gastric tumor (left) and ulcer (right)-IgG4 related
Hepatic tumors-IgG4 related
Kidney-tubulointerstitial nephritis-IgG4 related
Lacrimal gland-IgG4 related
Liver (inflammatory pseudotumor with sclerosing cholangitis)-IgG4 related
Positive staining - disease
● Plasma cells in IgG4+ related sclerosing disorders
End of Stains > IgG4
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