Clinical pathologic correlation of superficial corneal opacities in X-linked ichthyosis

X-linked ichthyosis is a relatively common oculodermal disorder. Characteristic corneal opacities are small punctate or filiform lesions and are located in the deep corneal stroma. In an unusual case, a 73-year-old man with X-linked ichthyosis and steroid sulfatase deficiency had superficial corneal opacities. The corneal opacities were granular in nature, involving the subepithelial and anterior stromal layers. The opacities resulted in irregular overlying corneal epithelium and were white-gray in color in direct illumination. Histopathologic and electron microscopic studies demonstrated abnormalities of the corneal epithelial basement membrane. The epithelial basement membrane was thickened with irregular extensions into Bowman's layers. Abnormal depositions of basement membrane protein were seen in the anterior stroma. These abnormalities may have resulted from increased production of basement membrane proteins by the corneal epithelium, resulting from hyperactive turnover of the basal layer.