title: The role of histopathological characteristics in distinguishing amalgam-associated oral lichenoid reactions and oral lichen planus.
abstract: OBJECTIVE
  To identify histological features that distinguish amalgam-associated oral lichenoid reactions (AAOLR) from oral lichen planus (OLP).
  
  
  METHODS
  Oral pathologists provided their opinion as to the possibility of distinguishing AAOLR and OLP histologically, the features important in distinguishing AAOLR from OLP and the diagnosis of 12 AAOLR and 12 OLP cases including the features that drew them to their conclusion.
  
  
  RESULTS
  There was considerable variation between pathologists in their ability to distinguish the AAOLR and OLP cases. The sensitivity and specificity for histological diagnosis were 40% and 32% respectively. There were four features that were used most commonly to discriminate between AAOLR and OLP: an inflammatory infiltrate located deep to superficial infiltrate in some or all areas; a focal perivascular infiltrate; plasma cells in the connective tissue and neutrophils in the connective tissue. Each was independently predictive of AAOLR or OLP (P < 0.028).
  
  
  CONCLUSIONS
  This study confirms the uncertainty of the diagnostic histological differences between AAOLR and OLP. Distinguishing these conditions should not rely on histology alone, but should be based on a synthesis of all available information including history, examination, histopathology and skin patch testing.
authors.affiliation: Department of Oral and Maxillofacial Medicine and Surgery, University of Sheffield School of Clinical Dentistry, UK. m.thornhill@sheffield.ac.uk
authors.forename: Martin H
authors.initials: MH
authors.lastname: Thornhill
authors.forename: Vidya
authors.initials: V
authors.lastname: Sankar
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Xu
authors.forename: A William
authors.initials: AW
authors.lastname: Barrett
authors.forename: Alec S
authors.initials: AS
authors.lastname: High
authors.forename: Edward W
authors.initials: EW
authors.lastname: Odell
authors.forename: Paul M
authors.initials: PM
authors.lastname: Speight
authors.forename: Paula M
authors.initials: PM
authors.lastname: Farthing
mesh_terms: D003238:Connective Tissue / Q000473:pathology; D032921:Consensus; D003723:Dental Amalgam / Q000009:adverse effects*; D003937:Diagnosis, Differential; D006801:Humans; D017676:Lichen Planus, Oral / Q000473:pathology; D017512:Lichenoid Eruptions / Q000139:chemically induced / Q000473:pathology*; D012680:Sensitivity and Specificity
chemical_list: D003723:Dental Amalgam