Contributor: Gordon K. Klintworth
Several types of congenital and acquired cyst can form in the orbit. They include the dermoid cyst [cyst - dermoid], epidermal inclusion cyst [cyst - epidermal inclusion], hematocele, teratoma, cystic schwannoma [schwannoma - cystic], choristomatous cyst [cyst - choristomatous], mucocele, pyocele, meningoencephalocele, cysticercosis, and hydatid cyst [cyst - hydatid]. The most frequent orbital cyst is the dermoid cyst. A cyst lined by a non-keratinizing epithelium containing goblet cells is usually unilateral and follows surgery or trauma (conjunctival epithelial inclusion cyst)[cyst - inclusion]. A similar cyst may form spontaneously with a predilection for the supratemporal orbit (primary non-keratinized epithelial orbital cyst). In contrast to the dermoid cyst epidermal appendages are not present within their wall. An orbital cyst is a feature of Delleman syndrome. Cystic lesions without an epithelial lining may be hematic, neurogenic or infectious in nature. A choristomatous cyst sometimes forms in the orbit and carcinoma arises from them on rare occasions.