An epithelial cyst in the cerebellopontine angle. Case report. A case of a benign epithelial cyst in the posterior cranial fossa is described. It had the unique histological feature of a double-layered cuboidal epithelial lining. Detailed immunohistochemical and electron microscopic studies supported an endodermal origin. The differential diagnosis and the histogenesis of epithelial cysts in the central nervous system are discussed. 