Epithelial cyst of the superior oblique muscle trochlea.

Most of the congenital orbital cysts are choristomas such as dermoid or epidermoid and only in a few cases they are epithelial. Clinically, they manifest as cystic movable formations mostly localized in the upper temporal quadrant of the orbit. We describe here the case of a 49-year-old man with an orbital cyst localized in the upper-nasal quadrant of the orbit and which was showing signs of a gradual enlargement and progression over the past weeks. Computed tomography revealed a cyst of 1.9 × 1.6 cm in size and located within the trochlea of the upper oblique muscle. The cyst was completely extirpated after orbitotomy performed by superciliary approach. Histopathology revealed a cyst with nonkeratinized cuboidal epithelium. Postoperative course was uneventful, without inflammation signs, and after 5 weeks excellent functional and aesthetic effects were achieved with no iatrogenic alteration of the ocular motility.