Barrett's esophagus

The normal esophagus (swallowing tube) is lined by a pinkish-white tissue called squamous epithelium[?]. Some people also have red stomach tissue (normal columnar epithelium) lining the bottom of the esophagus.

Barrett's esophagus is a condition in which the normal squamous epithelium of the esophagus has been replaced by an abnormal red columnar epithelium called specialized intestinal metaplasia. Specialized intestinal metaplasia is red like normal stomach tissue but does not look like stomach tissue under the microscope. Therefore, a biopsy (taking piece of tissue from the esophagus) is needed to diagnose Barrett's esophagus.