Electron-microscopical study of a Rathke's cleft cyst

The electron-microscopical appearance of a Rathke's cleft cyst is described. The cyst lining is seen to consist predominantly of secretory columnar epithelium, both ciliated and non-ciliated. There are also epidermoid cells occurring singly or in squamae. The histogenesis of Rathke's cleft cysts, in relation to craniopharyngiomas, is discussed.