Early Esophageal Adenocarcinoma with Non-Barrett's Columnar Epithelium Origin: Two Case Reports and a Literature Review

We herein report two cases of early esophageal adenocarcinoma derived from non-Barrett's columnar epithelium. Both patients, a 65-year-old woman and 60-year-old man, had elevated lesions on white-light imaging. Magnifying endoscopy revealed slightly irregular surface and vessel patterns, and both patients were successfully treated with endoscopic submucosal dissection. Histopathologically, both lesions comprised of well-differentiated gastric mucin phenotype adenocarcinoma. One lesion was accompanied by ectopic gastric mucosa, but the other was speculated to be ectopic gastric mucosa according to the tumor locus at the upper thoracic esophagus. Despite its rarity, endoscopists should consider the existence of adenocarcinoma derived from non-Barrett's columnar epithelium.