<prompt> Barretts esophagus is diagnosed bySquamous metaplasiaIntestinal metaplasiaSquamous dysplasiaIntestinal dysplasia  <response>: Ans. b Intestinal metaplasiaRef: Sabiston 19th edy page 1033 Barretts esophagus is characterized by metaplasia of esophageal squamous epithelium into columnar in distal esophagus. For diagnosis of Barretts esophagus it requires both endoscopically visible segment of columnar lining of distal esophagus and intestinal metaplasia showing goblet cells on biopsy. Barretts esophagus is the single most important risk factor for adenocarcinoma of esophagus. Adenocarcinoma develops at the squamo-columnar junction or within 2 cm from the junction. 