The esophagus is part of the digestive tract connecting the stomach to the throat. Is the inner lining (mucosa) of squamous cells. Sometimes these cells change and distorted, they are flat, and more and more space. The presence of these cells in a square or a cube, which extends from the bottom of the esophagus, the stomach in the throat, called Barrett’s esophagus. If not treated, in some cases, the abnormal cells can cause cancer of the esophagus.