Epithelial cells in symptomatic Rathke's cleft cysts. A light- and electron-microscopic study.

Epithelial cells composing symptomatic Rathke's cleft cysts were examined electron microscopically in two cases, and the fine structures were compared with those of the mucosa in the normal sphenoid sinus, of the normal choroid plexuses, and of a craniopharyngioma with goblet and ciliated cells. The Rathke's cleft cysts were composed of a single or pseudostratified epithelial layer abutting on the connective tissue. The epithelial cells were of four different kinds of cells, such as goblet, ciliated, flat, and basal cells. The flat cells containing bundles of tonofilaments and desmosomes were the squamous cells. They were present in a single-epithelial layer in both cases. The basal cells were present as small, wedge-shaped cells, even if the number was very small. The epithelial cells in Rathke's cleft cysts were more similar to those of the mucosa in the sphenoid sinus and those of a craniopharyngioma with goblet and ciliated cells than those of the choroid plexus. This study indicates the close relationship between Rathke's cleft cysts and mucosa in the sphenoid sinus or craniopharyngioma with ciliated and goblet cells.