Tutorial
Introduction
Slides
Edward J. Wladis, MD · Rudolph S. Wagner, MD
Dermoid cysts are choristomas that result secondary to a sequestration of embryonal surface ectoderm between fetal lines of bone closure.1-3 Histopathologically, dermoid cysts are composed of a keratinized squamous epithelium that is studded with dermal appendages (e.g., hair follicles, glandular structures). If composed solely of epidermal tissue, then dermoid cysts are referred to as epidermoid cysts. The lumen of dermoid cysts is made up of a mixture of keratin and lipid.1 Although dermoid cysts can occur at any location, 37% of dermoid cysts occur in the orbital or periorbital regions.
Dermoid cysts represent 3% to 9% of orbital tumors, and the majority initially present in children before 3 years of age. Dermoid cysts are the most common benign orbital tumors in children and represent 35% to 47% of all pediatric orbital masses.4-8 A second peak incidence occurs in the third and fourth decades of life, due to a progressive expansion of posteriorly located cysts with subsequent functional consequences.
These lesions often present superficially in the superotemporal orbital quadrant (i.e., immediately
anterior to the frontozygomatic suture) (Slide 1), but may be located at a variety of orbital sites
and may be fixed to the periosteum posteriorly. Tumors located nasally may be difficult to distinguish
from capillary hemangiomas or, rarely, encephaloceles (Slide 2). Many clinicians choose to obtain
imaging studies when the tumor is located nasally. Shields and colleagues1 devised a classification
system that is based on cyst location and attachments, dividing the lesions into juxtasutural, sutural,
and soft tissue lesions.
Generally, dermoid cysts are solitary, mobile, painless oval masses that follow a clinical course of slow and intermittent growth. Since these lesions have no malignant potential, then they can be observed if small, and carry no functional consequences. Progress is unpredictable in some cases and growth may be marked by deformation and erosion of the orbital bone and displacement of the globe.
Furthermore, lesions may result in optic foramen enlargement, lacrimal drainage obstruction, proptosis, and extraocular muscle compression or infiltration with subsequent diplopia. After trauma, dermoid cysts may leak, causing a localized granulomatous inflammation.1-7
Parents and surgeons may elect to remove the tumors when a child becomes ambulatory. Given the risks, the standard of care requires complete surgical excision of dermoid cysts and a variety of techniques have been used, depending on the location and extent of the cyst.
When these lesions are located in a juxtasutural position, a relatively straightforward approach can
be taken to the excision of the cyst. Generally, radiographic imaging is not indicated in these
patients. Most commonly, the lesions are located in a superficial superotemporal or superonasal
location and surgeons need not violate the orbital septum to remove them.
Initially described by Kronish and Dortzbach,9 the upper eyelid crease approach remains a popular technique. These authors recommend a skin incision along the lid crease with subsequent orbicularis incision.
Kronish and Dortzbach recommend downward pressure on the lesion with skin retraction. Careful dissection is then used to free the lesion. Ideally, the cyst is therefore removed in its entirety (Slide 3, Slide 4). The overlying skin is then closed with 6-0 suture. Nasal dermoids can be approached in a similar fashion (Slide 5).
Alternatively, an incision can be placed in an infra-brow location or immediately over the dermoid.
Skin retraction is then performed with rake retractors. Blunt dissection is carried out with Westcott
scissors, followed by sharp dissection. Throughout the procedure, surgeons must be mindful of the
various adhesions that are located across the body of the dermoid.
If necessary, the roof of the cyst may be elevated with forceps, allowing further dissection along the base. Again, complete removal of the cyst is preferable to removal of a ruptured cyst.
In either case, hemostasis is achieved throughout the procedure with wet field cautery. In addition, surgeons must be cautious of cyst rupture, as the internal keratin contents often result in a significant inflammatory reaction. Should rupture occur, the surgical field must be copiously irrigated with saline and perhaps an antibiotic solution. Careful exploration of the wound site should be performed to ensure that the dermoid has been removed.
Generally, deeper dermoid cysts involve bone, thereby creating an increased need for a more involved
surgical procedure (Slide 6). Posterior lesions are often clinically silent during the childhood period
that characterizes superficial dermoids. As such, posterior lesions are not diagnosed until later in
life. However, as they enlarge, these cysts may result in diplopia, proptosis, globe deformation, and
bone erosion. At that point, the dermoid cysts must be removed.
Sutural dermoids necessitate neuroimaging to determine the extent of the lesion.1,5 In their review of this subject, Shields and colleagues note the difficulty that is inherent to complete removal of deeper dermoid cysts, as they may have diffuse adhesions to bone. If imaging reveals a dural extension, then co-management with neurosurgical consultation may become necessary.
Meyer and colleagues5 reviewed their experience with temporal fossa dermoid cysts and suggested a carefully staged approach to their excision. They suggest a coronal approach with dissection that is deep to the facial nerve. A surgeon then dissects frontally in a subgaleal plane before moving subperiosteally to reach the orbital rim. The authors then advise reflection of the anterior temporalis muscle to expose the lateral orbit with subsequent removal of the lesion.
Soft tissue dermoid cysts should also be imaged preoperatively.1 These lesions are best removed via a lateral or anterior orbitotomy. If the lesions are intramuscular, then a lateral orbitotomy should be performed with careful muscle dissection to minimize intraoperative damage.
In addition to orbital manifestations, dermoids may also be found in epibulbar locations. These may
occur in isolation or be associated with Goldenhar syndrome. The majority of corneal limbal dermoids
are located inferotemporally and, generally, do not grow postnatally (Slide 7). Although corneal limbal
dermoids are cosmetically jarring, they can also result in astigmatism, corneal opacification, or
irritative symptoms. These symptoms often result in excision. Surgery is best performed via removal
along the corneal side at its base.
Experts do not recommend removal of the underlying tissue, and grafting is generally not necessary,
given the tissue planes along the mass base.10,11 Lipodermoids are conjunctival lesions located near
the temporal fornix (Slide 8). These are composed of adipose and connective tissue. Surgical excision
is difficult because the demarcation of the tumor from lacrimal gland tissue is often unclear.
Optimal management of dermoid cysts requires appropriate diagnosis with careful follow-up. Smaller, anterior cysts can often be observed if they are cosmetically acceptable and do not damage the surrounding structures. However, to avoid massive inflammation, these lesions are often excised.
A variety of approaches are appropriate to remove them, and complete excision is desirable. Deeper lesions often necessitate imaging and may require neurosurgical assistance. Should a surgeon be unable to completely remove the cyst, irrigation should be carried out with saline. Recurrences of dermoid tumors are unlikely.
- Shields JA, Kaden IH, Eagle RC, et al. Orbital dermoid cysts: Clinicopathologic correlations, classification, and management. The 1997 Josephine E. Schueler Lecture. Ophthalm Plast Reconstr Surg. 1997;13:265-276.
- Sherman RP, Rootman J, LaPointe JS. Orbital dermoids: Clinical presentation and management. Br J Ophthalmol. 1984;68:642-652.
- Bonavolonta G, Tranfa F, deConciliis C, et al. Dermoid cysts: 16 year survey. Ophthalm Plast Reconstr Surg. 1995;11:187-192
- Yeatts RP. Cystic tumors. In: Duane's Clinical Ophthalmology, revised edition. Tasman W, Jaeger EA, eds. Philadelphia: Lippincott-Raven; 1997.
- Meyer DR, Lessner AM, Yeatts RP, et al. Primary temporal fossa dermoid cysts. Ophthalmology. 1999;106:342-349.
- Youssefi B. Orbital tumors in children. J Ped Ophthalmol Strab. 1969;6:177-181.
- Nicholson DH, Green WR. Pediatric ocular tumors. New York: Masson; 1981.
- Shields JA, Bakewell B, Augsburger JJ, et al. Space-occupying orbital masses in children. Ophthalmolog. 1986;93:379-384.
- Kronish JA, Dortzbach, RK. Upper eyelid crease surgical approach to dermoid and epidermoid cysts in children. Arch Ophthalmol. 1988;106:1625-1627.
- Panton RW, Sugar J. Excision of limbal dermoids. Ophthalmic Surg. 1991;22:85-89.
- Wilson ME, Buckley EG, Kivli, JG, et al. Basic and Clinical Science Course, Section 6. San Francisco: American Academy of Ophthalmology. 2001-2002.