title: IgG4-related inflammatory pseudotumor: A systematic review of histopathological features of reported cases.
abstract: OBJECTIVE
  There is marked inconsistency in reporting the key features of IgG4-related inflammatory pseudotumor (IPT) cases. We aimed to analyze the various aspects of IgG4-related IPTs and to test the performance of the consensus criteria for their diagnosis.
  
  
  METHODS
  PubMed database was searched for IgG4-related IPT cases. The data regarding patient demographics, clinical presentation, laboratory findings, histopathological features, and treatment response are extracted and are presented here in a descriptive manner.
  
  
  RESULTS
  The study included 40 papers describing the clinicopathological features of 83 IPTs in 80 patients. Seventeen cases were diagnosed on biopsies; while remaining were diagnosed on excision specimens. Among these, 50 cases were categorized as highly suggestive and 24 cases as probable for IgG4RD; while nine cases had insufficient histopathological evidence of IgG4RD. Two cases diagnosed on biopsies having insufficient evidence of IgG4RD showed partial or no response to steroids; while 12/14 cases (85.71%) diagnosed on biopsies that were histologically suggestive or probable for IgG4RD showed prompt response to steroids.
  
  
  CONCLUSIONS
  Many reports have not specifically mentioned the full histopathological findings of IgG4-related IPTs that may hinder in refining the diagnostic criteria of IgG4RD. The IgG4-related IPTs diagnosed on biopsies with requisite features showed prompt response to steroids indicating specificity of histopathological findings in predicting treatment response.
authors.affiliation: a Department of Histopathology , Post Graduate Institute of Medical Education and Research, (PGIMER) , Sector 12 , Chandigarh , India.
authors.forename: Abhijit
authors.initials: A
authors.lastname: Chougule
authors.affiliation: a Department of Histopathology , Post Graduate Institute of Medical Education and Research, (PGIMER) , Sector 12 , Chandigarh , India.
authors.forename: Amanjit
authors.initials: A
authors.lastname: Bal
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006104:Granuloma, Plasma Cell / Q000276:immunology / Q000473:pathology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000473:pathology
chemical_list: D007074:Immunoglobulin G
keywords: IgG4; IgG4-related diseases; Inflammatory pseudotumor