<prompt> The basic pathology of Barretts esophagus is -Metaplasia of columnar cells to squamous cellsMetaplasia of squamous cells to columnar cellsDysplasia of esophageal epitheliumCardiac sphincter pressure disturbances  <response>: Ans. is b i.e., Metaplasia of squamous cells to columnar cells Barretts esophaguso Is metaplastic change of distal esophageal mucosa from normal squamous epithelium to columnar epithelium, in response to chronic gastro-esophageal reflux.o The junction between squamous esophageal mucosa and gastric mucosa moves proximally.o Three types of columnar epithelium have been described in Barretts esophagus:i Intestinal type - the most common typeii The junctional type andiii The gastric fundic typeo Barretts esophagus is a premalignant condition for adenocarcinoma esophaguso 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 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 remembero The hallmark of intestinal metaplasia is the presence of intestinal goblet cells. 