Conjunctival adnexal cysts and dermoids.

Of 128 cysts diagnosed clinically and pathologically as epidermoids and dermoids, 12 lesions were discovered that were lined by nonkeratinizing squamous epithelium with variable numbers of admixed goblet cells. Five lesions did not contain any adnexal structures in their walls and were designated as simple conjunctival cysts; seven lesions additionally displayed appendages in their walls and were diagnosed as conjunctival dermoids. Clinically, this group of 12 cysts differed from classic epidermoids and dermoids by their overwhelming superomedial location and absence of associated osseous defects. It is proposed that these nonkeratinizing cysts represent sequestrations of conjunctival-type epithelium, analogous to the displacements of keratinizing surface epidermis that are most commonly responsible for the production of classic epidermoids and dermoids. It is possible to confuse conjunctival cysts and dermoids with mucoceles.