title: Abundance of IgG4+ plasma cells in isolated reactive lymphadenopathy is no indication of IgG4-related disease.
abstract: OBJECTIVE
  IgG4-related disease is a recently recognized condition that can be associated with lymphadenopathy, with several histologic patterns and increased absolute number and ratio of immunoglobulin G4 (IgG4)-positive plasma cells. However, these findings are considered to be not exclusively specific for IgG4-related disease.
  
  
  METHODS
  The occurrence of the histologic patterns reported in patients with isolated lymphadenopathy was studied and correlated with the clinical presentation to determine their predictive value for IgG4-related lymphadenopathy.
  
  
  RESULTS
  We found cases meeting all histologic criteria for IgG4-related lymphadenopathy, without clinical signs of IgG4-related disease. The only pattern that was not seen in this series was an inflammatory pseudotumor-like picture.
  
  
  CONCLUSIONS
  Without a clinical suspicion of IgG4-related disease, these morphologic patterns and high numbers of IgG4-positive plasma cells should be interpreted with care to avoid an erroneous diagnosis of IgG4-related disease.
authors.affiliation: From the Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Laura Louzao
authors.initials: LL
authors.lastname: Martinez
authors.affiliation: From the Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Elza
authors.initials: E
authors.lastname: Friedländer
authors.affiliation: From the Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Jeroen A W M
authors.initials: JA
authors.lastname: van der Laak
authors.affiliation: From the Department of Pathology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands. k.hebeda@pathol.umcn.nl.
authors.forename: Konnie M
authors.initials: KM
authors.lastname: Hebeda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000276:immunology / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007150:Immunohistochemistry; D015994:Incidence; D007223:Infant; D008198:Lymph Nodes / Q000473:pathology; D008206:Lymphatic Diseases / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D010950:Plasma Cells / Q000276:immunology*; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G
keywords: IgG4; IgG4-related sclerosing disease; Lymphadenopathy