Barrett esophagus: endoscopic findings and what to biopsy.

Barrett esophagus (BE) is considered the precursor for nearly all cases of esophageal adenocarcinoma. The potential sequence from intestinal metaplasia to dysplasia to cancer can best be monitored by careful endoscopic observation and surveillance biopsies. The ability to diagnose BE, biopsy accurately, and appropriately monitor are requisites for all who care for patients with this disorder. The normal endoscopic anatomy of the esophagogastric junction region and the changes that are associated with BE are discussed. The relationship of the squamocolumnar mucosal junction to the proximal margin of the gastric folds and the distal extent of the linear esophageal vessels is the principal landmark for diagnosis. Chromoendoscopy with methylene blue and Lugol iodine will enhance endoscopic observation, thereby allowing directed biopsies. Biopsy forceps and technique are reviewed along with the when and where for surveillance biopsies. Since most dysplasia and intramucosal cancer is focal and invisible to the endoscopist, it is easy to understand why the sampling error exceeds 95% using a standard four-quadrant biopsy protocol. Currently, this sampling error can be reduced by four-quadrant biopsies at closer intervals and biopsies of even the most minor focal abnormalities of mucosa in the BE segment. Screening may be enhanced in the future depending upon successful development of new cytologic, spectrographic, and tomographic methods capable of identifying foci of dysplasia or cancer that can be confirmed by targeted biopsies.