Classification of Barrett's epithelium by magnifying endoscopy

Background: The specialized columnar epithelium of Barrett's esophagus can be detected by obtaining random or 4 quadrant biopsy specimens at conventional endoscopy. However, little is known about the fine mucosal structure of specialized columnar epithelium. Methods: Thirty patients with Barrett's esophagus were studied by magnifying endoscopy. The fine mucosal pattern (pit pattern) of 67 regions in Barrett's mucosa was recorded and compared with methylene blue staining. Histologic, mucin immunohistologic, and cell proliferation analyses of biopsy specimens were performed in relation to the pit patterns determined by magnifying endoscopy. Results: Pit pattern was classified into 5 types. Tubular and villous pit patterns were not only characteristics of both specialized columnar epithelium and methylene blue absorption, but also possessed an intestinal mucin phenotype with a high Ki-labeling index, whereas other pit patterns (dot and straight) did not have specialized columnar epithelium and were categorized as the gastric phenotype. The long oval pit pattern had an intermediate phenotype between gastric and intestinal. Conclusions: The classification of the superficial mucosal appearance of Barrett's epithelium by magnifying endoscopy reflects not only histologic features but also mucin phenotypes.