<prompt> Barretts esophagus is diagnosed by-Squamous metaplasiaIntestinal metaplasiaSquamous dysplasiaIntestinal dysplasia  <response>: The definition of Barretts esophagus BE, has evolved considerably over the past decade. Traditionally, BE was identified by the presence of columnar mucosa extending at least 3 cm into the esophagus. It is now recognized that the specialized intestinal-type epithelium found in Barretts mucosa is the only tissue predisposed to malignant degeneration. Consequently, the diagnosis of Barretts esophagus is presently made given any length of endoscopically identifiable columnar mucosa that proves on biopsy to show intestinal metaplasia. While long segments of columnar mucosa without metaplasia do occur, they are uncommon and are probably congenital in origin. The hallmark of intestinal metaplasia is the presence of intestinal goblet cells. Ref : Schwaz 9e p831 