The cardia: Esophageal or gastric? Critical reviewing the anatomy and histopathology of the esophagogastric junction

Background: Discrepancy exists regarding the anatomical allocation of the cardia: esophageal or gastric. With this review we aimed to clarify this issue. Methods: Using PUB MED, Scopus and Google we analyzed the recent literature (1889-2012) regarding the "esophageal" vs. the "gastric" cardia. Results: The synonymous use of the term cardia to describe the anti reflux mechanism within the distal portion of the esophagus and the proximal segment of the stomach nourished the misunderstanding, that the cardia represents a normal anatomical structure interposed between the tubular esophagus and the body of the stomach. Anatomical, histopathological and physiological studies revealed that what has been taken for gastric cardia in fact represents reflux damaged dilated distal esophagus (DDE). Since DDE is covered by columnar lined esophagus (CLE) it cannot be differentiated from the proximal stomach during regular endoscopy. However, the histopathology of multi level biopsies obtained from the endoscopically suspected esophagogastric junction (EGJ) serves to allocate the origin of the columnar lined foregut, esophageal (cardiac, oxyntocardiac mucosa, intestinal metaplasia) vs. gastric (oxyntic mucosa). Conclusions: Neither the esophagus nor the stomach contains a "cardia". The recent misconceptions regarding the foregut anatomy explain, why the innermost coverage of the reflux damaged esophagus is termed "cardiac mucosa". Thus the term should be reserved to name the histopathology of cardiac and oxyntocardiac mucosa, which develop due to gastroesophageal reflux within the distal esophagus.