Barrett's esophagus beneath squamous mucosa

Low power view demonstrates the glandular epithelium of Barrett's esophagus with an island of overlying squamous mucosa (arrows). Larger areas of squamous mucosa may render underlying Barrett's esophagus inapparent on endoscopy. This has been a concern in patients treated by some forms of ablative therapy in which replacement of columnar epithelium by squamous epithelium may not obviate the risk of malignant transformation from underlying Barrett's mucosa.