72 in recognition of BE ≥1 cm, however the RC dropped to 0.22 when less than 1 cm of columnar-lining was present. This is the endoscopic classification system currently suggested by the American College of Gastroenterology (4). A recent small study by Kinjo et al. (48) suggests that recognition of ultra-short segment BE may be improved using the Japanese EGJ reference point (the distal end of the palisade-shaped longitudinal vessels) rather Inhibitors,research,lifescience,medical than the traditional proximal limit of the linear gastric mucosal

folds currently utilized in the Prague C&M criteria, but more information is needed to determine if these results are reproducible and applicable outside of the Japanese population. Histologic features of Barrett’s

esophagus and PERK inhibitor dysplasia Clinicians and pathologists have defined BE to include not only a characteristic endoscopic appearance to the esophagus but also histologically confirmed intestinal metaplasia consisting of columnar epithelium Inhibitors,research,lifescience,medical with well-formed goblet cells (1). Goblet cells are recognized by a large cytoplasmic vacuole filled with blue-tinted mucin. During carcinogenesis, Inhibitors,research,lifescience,medical the tissue develops morphologic changes related to unregulated cell growth that can be recognized as dysplasia on microscopic examination (49). The spectrum of changes is subdivided into four clinically significant groups: negative for dysplasia, indefinite for dysplasia, low grade dysplasia, and high grade dysplasia. Patients with histologically confirmed dysplasia have been shown to have significantly increased risk of progression to EAC (33,50-52). Despite concerns over adequate sampling and imperfect Inhibitors,research,lifescience,medical intra- and interobserver reproducibility (particularly at the low end of the dysplasia spectrum), histologic

evaluation for dysplasia retains a key role in the surveillance of patients with BE (4,33,53). Due to the significance of identifying dysplasia, Inhibitors,research,lifescience,medical much work has gone into clarifying and refining the criteria used to interpret biopsies (33,54-57). The degree of dysplasia is determined by evaluating the cytology (nuclear and cytoplasmic features), architecture (relationship of glands and lamina propria), and degree of surface maturation (comparison of nuclear size within crypts to nuclear size at the mucosal surface) and interpreting these findings in conjunction Thymidine kinase with the amount of background inflammation. Features of each category of dysplasia are described below and summarized in Table 1. Table 1 Categories of dysplasia: Histologic features and suggested endoscopic surveillance (4,33,53) Negative for dysplasia – These biopsies can have a minimal amount of cytologicatypia but retain normal architecture, abundant lamina propria between glands, and appropriate maturation with a low nuclear:cytoplasmic ratio at the mucosal surface. The nuclei are regular, have smooth membranes, and are basally situated. If mitoses are present they are within the basal compartment.