These
congenital cysts may be present in the eyelid or within the orbit.The most common location is the superior temporal orbit.Grossly, these removed lesions consist of a large cyst with a
thickened wall that is filled with a yellowish, greasy or cheesy material
(#22132).Histopathologic
examination of the cyst wall reveals it to be lined by a keratinized,
stratified squamous epithelium(#22134).In contrast to an epidermoid cyst, dermoid cysts have skin or
dermal appendages such as hair follicles, sebaceous glands, and sweat
glands within the cyst lining (#22136) (#22134).Another variant of orbital choristomas is that of a dermal lypoma
(#22138).Histopathologically, these lesions show a large amount of benign,
septated fatty tissue interspersed with areas of dense fibrous connective
tissue.
