Clinical and pathologic description of 17 cases of corneal intraepithelial neoplasia.

In 17 patients with corneal intraepithelial neoplasia (dysplasia), the epithelium formed a gray plaque at the corneal limbus adjacent to a conjunctival papilloma in seven cases, leukoplakia in six cases, a pterygium in one case, and a pinguecula in one case. The lesion was an extension of a similar neoplastic process of the conjunctiva in 15 cases, was associated with chronic conjunctivitis in one case, and was isolated to the cornea in one case. Fine white dots mottled the opalescent, ground-glass sheet, whose fimbriated leading edge consisted of sharply demarcated gray fingers that extended to the visual axis in some cases. The disorder can wax and wane spontaneously, shown in one case observed for 16 years. Histopathologically, the thick, hypercellular corneal epithelium abutted sharply against adjacent normal epithelium and demonstrated both cellular pleomorphism and poor intercellular adhesion in the deeper layers. The adjacent conjunctival neoplastic lesions ranged from mild dysplasia to invasive squamous cell carcinoma. Ultrastructurally, the corneal epithelium showed a marked decrease in desmosomal attachments, an abundance of intracytoplasmic filaments characteristic of keratin, and a loss of epithelial basement membrane and hemidesmosomes. The lesion did not extend into Bowman's zone. We classify this dysplastic process as a mild form of corneal intraepithelial dysplasia, a term used to designate the spectrum of epithelial changes ranging from dysplasia to carcinoma in situ. The virulence of the corneal lesion itself is low.