Does Cytokeratin7/20 immunoreactivity help to distinguish Barrett's esophagus from gastric intestinal metaplasia? Results of a prospective study of 75 patients.

Barrett's esophagus is a recognized risk factor for the development of esophageal dysplasia and carcinoma. Unfortunately, gastric incomplete intestinal metaplasia arising in Short Segment Barrett's esophagus can be indistinguishable histologically on hematoxylin/eosin stains. Distinct patterns of CK 7 and CK 20 immunohistochemical expression have been demonstrated to be both highly sensitive and specific for Barrett's esophagus, but have not been found in gastric metaplasia. The aim of our study was to test whether immunostaining with CK 7/20 helps to distinguish between Barrett's epithelium and gastric incomplete metaplasia. Cases of long segment Barrett's esophagus, short segment Barrett's esophagus, and cases with a normal gastroesophageal junction, as well as specimens with gastric antral intestninal metaplasia, were examined: three patterns were defined. Barrett's pattern (superficial CK 20 staining; superficial and crypt CK 7 staining); gastric pattern (superficial and crypt staining of both markers); other patterns (different from Barrett and gastric types). Seventy-five patients were enrolled in this study, 26 with long segment Barrett's esophagus, 21 with short segment esophagus, 13 with intestinal metaplasia of the cardia, and 18 with antral intestinal metaplasia. The Barrett pattern showed a high specificity of 97%, but a sensitivity of only 30% in patients with short segment Barrett esophagus. Our results do not confirm the hypothesis that CK 7/20 immunostaining can be used for a reliable differentiation between incomplete intestinal metaplasia and Barrett's epithelium.