Long segments of columnar-lined lower esophagus are not always metaplastic.

The presence of columnar epithelium in the esophagus is associated with two conditions: Barrett's esophagus and heterotopic gastric mucosa. The former results from the metaplastic replacement of the normal distal squamous esophageal lining, is associated with gastroesophageal reflux and is a pre-neoplastic condition. The second is thought as a congenital condition, resulting from the incomplete squamous epithelialization of the esophagus during embryologic development. It is found mainly in the cervical esophagus. Histologically, Barrett's esophagus is composed of an admixture of cardiac mucosa, oxintocardiac mucosa and intestinal metaplasia. Most of heterotopic gastric mucosa consists of oxynticmucosa where the mucosal glands are straight and composed of parietal and chief cells.There are few reports of heterotopic gastric mucosa in the lower esophagus, generally presenting as small islands. In the present report, a series of four cases of large lower esophageal heterotopic gastric mucosa is described. All patients were initially misdiagnosed with Barrett's esophagus and referred for surveillance. The correct diagnosis was based in endoscopic and histological features. In all, a circular tiny strip of squamous mucosa was observed at endoscopy between the lower end of the columnarlined esophagus and the esophagogastric junction, defined as the proximal end of the gastric folds. Biopsy samples taken from the columnar-lined segments of the four patients showed pure oxyntic mucosa.When columnar-lined esophagus is observed in the distal esophagus not in continuity with gastric mucosa, the diagnosis of heterotopic gastric mucosa must be thought and confirmed histologically by the presence of pure oxyntic mucosa.