<prompt> Barretts oesophagus is :Lower oesophagus lined by columnar epitheliumUpper oesophagus lined by columnar epitheliumLower oesophagus lined by ciliated epitheliumLower oesophagus lined by pseudostratified epithelium  <response>: Barretts esophagus Is metaplastic change of distal esophageal mucosa from normal squamous epithelium to columnar epithelium, in response to chronic gastro-esophageal reflux.The junction between squamous esophageal mucosa and gastric mucosa moves proximallyThree types of columnar epithelium have been described in Barretts esophagus:intestinal type - the most common typethe junctional type andthe gastric fundic typeBarretts esophagus is a premalignant condition for adenocarcinoma esophagusThe 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 the Barretts mucosa is the only tissue predisposed to malignant degeneration. Consequently, the diagnosis of BE is presently made given any length of endoscopically indentifiable columnar mucosa that proves on biopsy to show intestinal metaplasia. - Schwartz 9e p831 8e, p868Also rememberThe hallmark of intestinal metaplasia is the presence of intestinal goblet cells. 