Metaplastic columnar cells in Barrett's esophagus: a common and neglected cell type.

Goblet cells are considered by most to be a prerequisite for the diagnosis of Barrett's esophagus. Columnar cells that are alcian blue (AB) positive (as are goblet cells) are commonly observed in the surface epithelium of Barrett's esophagus, but their distribution in relation to goblet cells has not previously been defined. The authors analyzed the prevalence and distribution of these cell types in the surface but not pit epithelium (where they may sometimes be present in normal gastric mucosa). The distribution of the AB-positive columnar cells was mapped out in the entire mucosa of nine esophagectomy specimens, resected for Barrett's-associated high-grade dysplasia or carcinoma, and compared with other cell types, especially goblet cells. AB-positive goblet and columnar cells were present in 87.1% +/- 5.6% and 85.7% +/- 5.9%, respectively, of the evaluated sections of Barrett's mucosa, whereas gastric-type, AB-negative cells were observed in 46.3% +/- 8.7% of the sections. In 53% of the sections, the surface epithelium contained more than 25% AB-positive cells, and in more than three quarters of these sections, AB-positive columnar cells were the dominant AB-positive cell type. No difference in the distribution of the AB-positive epithelial cells was noticed between the proximal and distal halves of the Barrett's mucosae. In the cardia region, seven of nine cases showed a few scattered AB-positive columnar cells, and five of nine cases showed a few scattered goblet cells. No AB-positive cells were found in fundic gland mucosa. These findings indicate that the metaplastic AB-positive columnar cells are more prevalent than goblet cells. They may be analogous to incomplete metaplastic cells of the stomach, and, therefore, their role in the development of neoplasia needs further study.