Reflux esophagitis and Barrett esophagus.

: This chapter reviews the pathologic aspects of gastroesophageal reflux and reflux esophagitis. High-grade and low-grade changes due to reflux are discussed in the context of peptic complications such as hemorrhage, ulcer, stricture, and acquisition of Barrett mucosa. The limitations of histopathologic criteria in squamous epithelium for the diagnosis of reflux esophagitis, such as elongated vascular papillae and widened basal zone, are described. The pathogenesis of and criteria for diagnosis of Barrett esophagus are addressed. The neoplastic complication of adenocarcinoma arising in Barrett esophagus is discussed. Finally, the implications of columnar epithelial dysplasia and potential markers in Barrett mucosa for surveillance of Barrett patients are reviewed.