Adenoid cystic carcinoma of the esophagus: a light and electron microscopic study.

The light and electron microscopic appearances of adenoid cystic carcinoma of the esophagus are presented. Typical light microscopic features of adenoid cystic carcinoma were seen, but a unique additional feature was the presence at one edge of the tumor of gland-like structures lined entirely by tumor cells and opening onto an intact esophageal epithelium. Electron microscopy showed cystic spaces containing replicated basement membrane surrounded by epithelial cells with occasional myoepithelial cells at the interface. Rare lumina were seen between the cells with microvilli projecting into them. Occasional epithelial cells contained granules of neurosecretory tape. Both the light and electron microscopic findings strongly support an origin from the intercalated duct of esophageal mucus glands. The paucity of gland lumina may represent a lesser degree of differentiation which would accord well with the known biological aggressiveness of the tumor at this site.