In medicine, Barrett esophagus is "a condition with damage to the lining of the lower esophagus resulting from chronic acid reflux (esophagitis, reflux). Through the process of metaplasia, the squamous cells are replaced by a columnar epithelium with cells resembling those of the intestine or the salmon-pink mucosa of the stomach. Barrett's columnar epithelium is a marker for severe reflux and precursor to adenocarcinoma of the esophagus." 
Barrett esophagus may be overdiagnosed.
- Anonymous (2021), Barrett esophagus (English). Medical Subject Headings. U.S. National Library of Medicine.
- Ganz RA, Allen JI, Leon S, Batts KP (2014). "Barrett's esophagus is frequently overdiagnosed in clinical practice: results of the Barrett's Esophagus Endoscopic Revision (BEER) study.". Gastrointest Endosc 79 (4): 565-73. DOI:10.1016/j.gie.2013.09.024. PMID 24262638. Research Blogging.