Barrett esophagus is a precancerous condition and complication of gastroesophageal reflux disease that predisposes for esophageal adenocarcinoma. Chronic exposure of the esophageal mucosa results in an adaptive response and replacement of stratified squamous epithelium with metaplastic columnar epithelium.
Patients suffering from BE are usually of advanced age and have a medical history of chronic GERD. The latter is typically associated with acid regurgitation, heartburn, retrosternal chest pain, and dysphagia. It has been suggested that individuals previously diagnosed with GERD-related erosive esophagitis are more likely to develop BE , but these data are primarily of epidemiological relevance since a considerable subset of BE patients remains entirely asymptomatic. Accordingly, it has been recommended to perform annual or biannual esophagoscopy examinations in men who have presented GERD-associated symptoms for more than five years if either two of the following risk factors are present: age >50 years, Caucasian, family history of BE, obesity, smoker . These features define the "classical" BE patient. Eventually, BE may constitute an incidental finding encountered during endoscopic procedures realized for non-related reasons.
Progression to esophageal adenocarcinoma occurs in about 0.5% of BE patients per year . Disease progression may entail additional symptoms like exacerbated dysphagia, persistent cough, weight loss, as well as symptoms associated with metastatic adenocarcinoma  .
Diagnosis of BE is based on endoscopic findings and histopathological analyses of biopsy specimens. With regards to the former, metaplastic columnar epithelium is of intense red color and confers a velvety aspect to the esophageal mucosa. In contrast, healthy stratified squamous epithelium appears pale and glossy .
BE is frequently referred to as "intestinal metaplasia" because affected mucous membranes resemble small intestinal epithelium. It has to be noted, though, that columnar epithelium as observed in BE patients differs considerably from intestinal mucous membranes, e.g., with regards to gene expression profiles and the cells' ability to differentiate . The pathohistological picture is dominated by pathognomonic mucin-containing acid, Alcian blue-staining goblet cells and periodic acid-Schiff positive cells that harbor neutral mucin . Endocrine and Paneth cells have been identified in samples obtained from BE patients.
Barrett esophagus (BE) may complicate gastroesophageal reflux disease (GERD). In detail, chronic exposure of the esophageal mucosa to gastric acid results in the replacement of stratified squamous epithelium with metaplastic columnar epithelium . In accordance with the disease' etiology, mucosal alterations consistent with BE affect distal portions of the esophagus. However, tissue samples should not be obtained within less than 1 cm of the esophagogastric junction in order to guarantee reliable results . BE is considered a precancerous condition and affected individuals are predisposed for esophageal adenocarcinoma .
BE patients are generally prescribed proton pump inhibitors and antacids, and these drugs may alleviate symptoms associated with GERD. Unfortunately, they are unable to reverse structural remodeling processes affecting the esophageal mucosa. Treatment options available to date comprise thermal, photochemical, or mechanical, endoscopic ablation and esophagectomy .