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Present diagnosis and management of gastroesophageal reflux disease (GERD) has resulted in a dramatic increase in the incidence of esophageal adenocarcinoma. This is due to failure to identify pathologic changes of early GERD; at present, pathology is limited to management of Barrett esophagus (BE).
Convincing evidence have confirmed that cardiac mucosa distal to the squamocolumnar junction in the endoscopically normal person is a metaplastic GERD-induced esophageal epithelium, and not a normal proximal gastric epithelium.
When cardiac mucosa is recognized as a metaplastic esophageal epithelium, it becomes self-evident that the present endoscopic definition of the gastro-esophageal junction is incorrect, and there exists a dilated distal esophagus (DDE) in what is incorrectly termed the “gastric cardia” presently mistaken for proximal stomach. It also becomes clear that the length of the DDE correlates with the presence and severity of GERD and represents the pathology of the entire spectrum of GERD. Further, it allows recognition that the DDE, measured as the gap between esophageal squamous epithelium and gastric oxyntic mucosa that is composed of cardiac mucosa, represents the pathologic anatomy of damage to the abdominal segment of the lower esophageal sphincter (LES).
The new understanding of the significance of cardiac mucosa provides a new and highly accurate histologic method of assessment of LES damage, the primary cause of GERD. This opens a new door to complete histologic assessment of GERD from its etiologic standpoint and to new research that permit early diagnosis of GERD at its outset. Ultimately, such early diagnosis has the potential to reverse the increasing trend of esophageal adenocarcinoma.