Histologic changes in gastroesophageal reflux.

Three aspects of the esophageal mucosal injury that occur in gastroesophageal reflux disease are discussed in this article. First, the histologic changes in the squamous epithelium-lined esophagus are variable. Some patients with reflux symptoms do not have histologic evidence of inflammatory cell infiltration within the mucosa, but rather may have more subtle effects of mucosal injury, namely, thickening of the basal regenerative layer, elongation of the papillae, or intraepithelial eosinophils. However, these more subtle findings often are merely confirmatory of other clinical indicators of gastro-esophageal reflux; they may have their most practical application to the research investigation of reflux disease. Second, the presence of esophageal mucosal inflammation may adversely affect lower esophageal sphincter function. This phenomenon can be demonstrated in the cat model. Whether it is operative in humans is unclear. Finally, the development of columnar metaplasia (Barrett's epithelium) is more than a histologic curiosity because this condition confers an increased risk of developing adenocarcinoma of the esophagus. Among several unanswered questions about Barrett's epithelium is what is an appropriate surveillance program for patients with Barrett's epithelium to detect the presence of, or predict the development of, cancer?