The histologic hallmark of BE is:
A. Columnar epitheliumThe definition of BE has evolved considerably over the past decade. Traditionally, BE was identified by the presence of columnar mucosa extending at least 3 em into the esophagus. It is now recognized that the specialized, intestinal-type epithelium found in the Barrett mucosa is the only tissue predisposed to malignant degeneration. Consequently, the diagnosis of BE is presently made given any length of endoscopically identifiable columnar mucosa that proves, on biopsy, to show IM. Although long segments of columnar mucosa without IM do occur, they are uncommon and might be congenital in origin.
The hallmark ofiM is the presence of intestinal goblet cells. There is a high prevalence of biopsy-demonstrated IM at the cardia, on the gastric side of the squamocolumnar junction, in the absence of endoscopic evidence of a columnar-lined esophagus ( CLE). Evidence is accumulating that these patches of what appears to be Barrett in the cardia have a similar malignant potential as in the longer segments, and are precursors for carcinoma of the cardia.