Congenital epithelialization of the posterior cornea.

A 6-month-old infant boy who had a unilateral congenital corneal opacification with adhesions of abnormal iris to the posterior cornea underwent corneal transplantation. Pathologic examination of the excised cornea showed a central defect in Bowman's layer, an absent Descemet's membrane, and multilayered squamous epithelium replaced the endothelial layer. Electron microscopy confirmed that these cells had epithelial characteristics with numerous desmosomes, microvilli, and abundant cytoplasmic tonofibrils. While the pathogenesis remains obscure, a metaplastic process early in gestation probably resulted in the presence of epithelial cells in the endothelial layer.