Scanning electron microscopic study of the epithelial-mesenchymal junction of the esophagus.

This is a study of the appearance by scanning electron microscopy of the stromal papillae and basal lamina at the epithelial-mesenchymal junction of the human esophagus. After incubation in 2N sodium bromide at 60 degrees C. for 1 hour, the squamous epithelium was removed gently under the dissecting microscope from esophageal specimens from six normal human esophagi. The remaining stromal surface covered by an intact smooth basal lamina was examined "en face" by scanning electron microscopy. Transmission electron microscopy confirmed that the separation following NaBr was between the basal cell plasma membranes and the basal lamina, and that the basal lamina and subbasal connective tissue were well-preserved and attached normally to each other. Complex topographical patterns consisting of various numbers of simple and branched papillae and blade-like stromal folds were observed. Papillae had helical contours because of the spiral capillaries within them. Subepithelial capillaries were also visible as interconnecting linear ridges in the interpapillary zones. There was great variation in papillary length and patterns between individuals, but there was no difference in patterns or papillary length in sections taken from lower, middle, and upper portions of the esophagus in a given patient. These findings suggest that comparisons of absolute length of stromal papillae in different individuals should not be interpreted as a pathologic change. The results reveal an unexpected complexity in this epithelial-stromal interface.