title: The prevalence of IgG4-positive plasma cells in hypophysitis: a possible relationship to IgG4-related disease.
abstract: OBJECTIVE
  Hypophysitis is a rare chronic inflammation of the pituitary gland corresponding currently to six histopathological subtypes. Among them, immunoglobulin- G4-related hypophysitis was recently added in this classification. The aim of this study was to perform a retrospective histopathological and immunohistochemical analysis to evaluate the prevalence of IgG4-related hypophysitis and review reported cases.
  
  
  METHODS
  All samples of hypophysitis from Lariboisiere hospital were reviewed by two pathologists to assess their subtypes. An immunohistochemistry against IgG4 and IgG was performed. Slides were numerized, and IgG4-positive plasma cells and IgG plasma cells were counted in three high-power fields to evaluate the ratio.
  
  
  RESULTS
  Eight cases were included: 5 lymphocytic hypophysitis, 1 granulomatous subtype, and 2 IgG4-related hypophysitis, affecting two young women without other coaffected organ.
  
  
  CONCLUSIONS
  Our results show that IgG4-related hypophysitis is not an exceptional entity. Storiform fibrosis and obliterative phlebitis, histopathological characteristics of IgG4-related disease in other organs, are lacking in pituitary lesions. This study proves the interest of immunohistochemistry for diagnosis of IgG4-related hypophysitis. Due to the sensibility of IgG4-disease to steroids in other organs, this finding could be of clinical relevance.
authors.forename: Arnault
authors.initials: A
authors.lastname: Tauziede-Espariat
authors.forename: Marc
authors.initials: M
authors.lastname: Polivka
authors.forename: Schahrazed
authors.initials: S
authors.lastname: Bouazza
authors.forename: Philippe
authors.initials: P
authors.lastname: Decq
authors.forename: Gilles
authors.initials: G
authors.lastname: Robert
authors.forename: Marie
authors.initials: M
authors.lastname: Laloi-Michelin
authors.forename: Homa
authors.initials: H
authors.lastname: Adle-Biassette
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000276:immunology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007150:Immunohistochemistry; D010900:Pituitary Diseases / Q000276:immunology* / Q000473:pathology; D010950:Plasma Cells / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D007074:Immunoglobulin G