Large Cell Acanthoma of the Conjunctiva: Clinicopathologic and Immunohistochemical Features.

Large cell acanthoma (LCA) was first described as a lesion on sun-exposed skin. All LCAs feature keratinocytes twice the size of normal cells (cytomegaly). Although infrequently diagnosed in the skin, it has been even more rarely described by ophthalmic pathologists in the eyelid skin and the conjunctiva. This report describes the third case of a conjunctival epithelial LCA, with the first published clinical photograph highlighting its leukoplakic and well-circumscribed character, as well as the most thorough analysis of the immunohistochemical features of this lesion. It is contrasted with squamous dysplasias and papillomas of the conjunctiva. A review of previous conjunctival LCA lesions discloses frequent recurrences after initial surgery and the remote but real potential for squamous dysplastic transformation. Immunohistochemical stains for certain cytokeratins, p53, and Ki-67 (proliferation index) will in the future be particularly helpful in establishing an early and accurate diagnosis of conjunctival LCA.