History
Patients generally complain of a mass, which is visible in the orbital area. Growth of these lesions is generally slow. Occasionally, a history of inflammation will be present.
Patients with deep orbital dermoids may present with marked proptosis and downward displacement of the eye.
In adults, dermoids may become symptomatic for the first time and grow considerably over a year. Based on this fact, some conclude that these lesions may be dormant for many years or have intermittent growth.
Physical
Children
The most common location is in the superior temporal aspect of the orbit. The second most common location is in the superior nasal aspect of the orbit.
Lesions located superotemporally are generally smooth, firm subcutaneous masses attached to the orbital rim in the region of the zygomaticofrontal suture.
The mass is generally less than 1 cm in diameter, nontender, and oval in shape.
Little displacement of the globe usually occurs.
Orbital dermoid cysts are not attached to the skin, which helps differentiate them from sebaceous cysts. The cyst usually is tethered to the periosteum of the bone near suture lines, including the sinuses or intracranial cavity. [4]
Adults
The cysts are palpated less easily and have more vague borders. They are more likely to displace the globe and may erode their way into adjacent structures.
Inflammation
If the cyst ruptures, either spontaneously or with trauma, an inflammatory response may be seen. This response may be limited to injection of the conjunctiva or may be severe and mimic orbital cellulitis. Occasionally, subconjunctival droplets of fat are seen. [5]
Neurologic findings
Rarely, the cyst may press on the optic nerve and produce symptoms of optic nerve compression; reduced visual acuity, color vision and brightness perception, and a relative afferent pupillary defect.
More rarely, the cyst may induce diplopia by physically restricting movement of the globe or by compressing cranial nerves III, IV, or VI.
Causes
No known causes for orbital dermoid exist.
Other diagnostic considerations include the following:
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Ruptured dermoid cysts may mimic rhabdomyosarcoma
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Pediatric metastatic cancers
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Orbital cellulitis
Complications
The dermoid cyst may displace the globe, depending on the location of the cyst.
Orbital dermoid cysts may cause neurologic complications if they compress the optic nerve or cranial nerves III, IV, or VI.
If the cyst ruptures, a marked inflammatory response follows.
Operative complications are those common to other orbitotomy procedures. Damage to the eye or adnexal structures, motility restriction, infection, inflammation, and hemorrhage may occur. Partial excision of the dermoid cyst may result in persistent inflammation, a draining sinus, or recurrence.
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Temporal-zygomatic suture line on the lateral orbital wall. The location of the periosteal attachment of most orbital dermoids.
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Orbital dermoid.
