title: Histologic definition of gastro-esophageal reflux disease.
abstract: OBJECTIVE
  To review recent data supporting the development of new histology-based definitions of gastro-esophageal reflux disease (GERD).
  
  
  RESULTS
  Three precisely definable columnar epithelial types--cardiac, oxyntocardiac and intestinal--may be interposed between esophageal squamous epithelium and gastric oxyntic (acid secreting) mucosa. This enables definition of a new histologic concept: the squamo-oxyntic gap. The squamo-oxyntic gap is zero or very small in autopsies performed on patients without evidence of GERD. The gap progressively increases in length with the severity of GERD, indicating that the squamo-oxyntic gap is a marker for chronic GERD. The distal part of the gap lines gastric-type rugal folds and, therefore, is distal to the present endoscopic definition of the gastro-esophageal junction. I contend that this distal gap segment (which has esophageal submucosal glands) is actually the dilated distal esophagus; this is the pathologic correlate of destruction of the abdominal segment of the lower esophageal sphincter. The dilated distal esophagus is mistaken for 'gastric cardia' by present endoscopic definitions.
  
  
  CONCLUSIONS
  I believe that these data support the adoption of novel histologic definitions of GERD as follows: the presence of any squamo-oxyntic gap defines GERD; the length of the gap is a measure of severity of chronic GERD; and the presence of intestinal metaplasia in the gap defines Barrett esophagus and cancer risk.
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA. ptchandr@usc.edu
authors.forename: Parakrama T
authors.initials: PT
authors.lastname: Chandrasoma
mesh_terms: D001471:Barrett Esophagus / Q000473:pathology; D018450:Disease Progression; D004848:Epithelium / Q000473:pathology; D004938:Esophageal Neoplasms / Q000473:pathology; D004945:Esophagoscopy; D005764:Gastroesophageal Reflux / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D011230:Precancerous Conditions / Q000473:pathology; D012720:Severity of Illness Index