Origins of the Glandular Mucosae in the Gastro-Esophageal Junction—A Study in a South Asian Population With Low Incidence of Esophageal Adenocarcinoma

Introduction: Gastro-esophageal junction (GEJ) is subjected to controversy due to limited knowledge of its anatomy and histology. We conducted a study to determine the origins of the glandular mucosa at GEJ. Methods: Three groups were used, groups A and B, with grossly normal GEJs and Group C with endoscopic evidence of reflux damage. Group A comprised 23 esophago-gastrectomies, group B, 112 dyspeptic patients with normal GEJ and group C, 46 dyspeptic patients with reflux damaged GEJs. Origins of cardiac mucosa (CM), intestinal metaplasia (IM), and oxyntocardiac mucosa (OCM) were determined by studying their associations with esophageal markers (EM): esophageal glands and ducts, multilayered epithelium and squamous islands highlighted with immunohistochemistry. The histological gap between esophageal squamous and gastric oxyntic mucosa containing CM/IM/OCM was considered as squamo-oxyntic (SO) gap. Results: In Group A and B, a microscopic SO gap was detected in 58.1% and the prevalence of CM was 43% and IM 4.4% and CM 89.7%; 100% IM were associated with EM. Prevalence of CM and IM, in group C was 56.5% and 15.2% respectively and EM were present in 85.7% IM and 88.5% CM. When only OCM is present, 41.2% were proven to be metaplastic. Conclusions: Even when GEJ is grossly normal, microscopic columnar lined esophagus was common at the GEJ and with increased sampling and using several EM almost all CM and IM at the GEJ could be proven to be metaplastic in origin.