dermoid cysts, gliomas, and encephaloceles evaluation and treatment

Dermoid cysts, gliomas, and encephaloceles:evaluation and treatment

Jeffrey C. Posnick, DMD, MD, FRCS(C), FACSa,c,and Bernard J. Costello, DMD, MDb,c,*

aDepartments of Plastic Surgery, Otorhinolaryngology/Head and Neck Surgery,

Oral and Maxillofacial Surgery, and Pediatrics, Georgetown University School of Medicine,

Washington, DC, USAbDepartments of Otorhinolaryngology, Head and Neck Surgery, and Oral and Maxillofacial Surgery,

Georgetown University School of Medicine, Washington, DC, USAcPosnick Center for Facial Plastic Surgery, Chevy Chase, MD, USA

A spectrum of congenital frontonasal malformations exists, with encephaloceles at one end,

dermoid sinus cysts at the other, and gliomas in between. The encephalocele is a herniation of

brain and meninges, and the glioma is composed of glial tissue (i.e., nonnervous cellular ele-

ments of nervous tissue), which is separate from the brain. In contrast to these neuroectodermal

malformations, the dermoid cyst is a somatic ectodermal anomaly in the region.

Differentiating between encephaloceles and gliomas may be difficult. The glioma is firm andnot compressible, whereas the encephalocele is not as firm and is compressible to some extent.

Pulsation and increase in size on straining may be noted in encephaloceles. The diagnosis is con-

firmed by a CT scan or MR image. Persistence of ectodermal tissue anywhere anterior to the

foramen cecum within the prenasal space, extending to the nasal tip, produces a dermoid cyst

or sinus. Glabellar cysts or sinuses can be explained by persistence of the same tissue anterior

to the region of the nasofrontal fontanelle. Failure of obliteration of the dural process, which

normally exits through the foramen cecum in early embryonic life, sets the stage for develop-

ment of dura-lined cysts, including ‘‘dumbbell’’—shaped lesions with elements above and belowthe foramen.

Embryology

The most widely accepted theory of the embryogenesis of nasally located encephaloceles,

gliomas, and dermoid cyst sinus tracts was proposed by Grunwald in 1910 and later elaborated

by Pratt. It states that during early embryologic development, the nose consists of three layers:

ectoderm, mesoderm, and a deeper layer of cartilage that is part of the cartilaginous capsule.

Later, at 50 to 60 days’ gestation in human beings, the nasal and frontal bones develop by in-tramembranous ossification of the mesoderm, but they remain separated by a space called the

fonticulus nasofrontalis. Between the nasal and frontal bones and the deeper cartilaginous cap-

sule, a space extends from the base of the skull to the nasal tip. A small projection of dura ex-

tends into this space (with or without arachnoid and neural tissue). The dura projection may

extend (1) anteriorly through the fonticulus nasofrontalis or (2) inferiorly through the develop-

ing frontal bones into the prenasal space. These diverticula come into contact with the skin and

may adhere to it. Normally, the dural diverticula regress with time. The nasal process of the

frontal bones separates the skin from the dura, and the projection of dura becomes encircled

Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 85–99

* Corresponding author. 100 Anderson Street, Apt. 435, Pittsburgh, PA 15212.

E-mail address: [email protected] (B.J. Costello)

1061-3315/02/$ - see front matter � 2002, Elsevier Science (USA). All rights reserved.

PII: S 1 0 6 1 - 3 3 1 5 ( 0 1 ) 0 0 0 0 4 - X

by an opening in the frontal bones called the foramen cecum. The foramen cecum eventually

fuses with the fonticulus nasofrontalis in the area of the future cribriform plate and in so doing

obliterates neuroectodermal connections. Incomplete closure at the glabella gives rise to spread-

ing of the nasofrontal suture or to a canal through the bone. Incomplete closure of the midlineanterior skull base leads to a wide foramen cecum with a distorted or bifid crista galli. Depend-

ing on the patency of the diverticulum and its contents, the resulting lesion can be a dermal cyst

or sinus tract, a glioma, or an encephalocele at the glabella or within the prenasal space.

Nasal dermoid sinus cysts

Midline nasal dermoid sinus cysts are rare congenital lesions that result from faulty embryo-logic development. They are distinct from other facial dermoids in their potential to exist as a

cyst, sinus, or fistula, which also can involve deeper contiguous structures, and in their potential

for intracranial extension. Failure to recognize and treat this condition promptly may lead to

primary or recurrent (persistent) infections and result in meningitis or brain abscess. The nasal

dermoid sinus cyst constitutes 1% to 3% of all dermoids of the body and 3% to 12% of dermoid

cysts found in the head and neck (Fig. 1). Most cysts that occur arise sporadically; however,

reports of familial occurrence have been documented. Associated congenital anomalies are

Fig. 1. A 3.5-year-old boy who was born with a cystic mass over the dorsum of the nose that was indicated by clinical

and radiologic examination was determined to be a midline nasal dermoid sinus cyst extending intracranially underwent

excision through a direct nasal and coronal (scalp) incision with immediate reconstruction. (A) Frontal view before

surgery. (B) Frontal view 3 years after excision and reconstruction. (C) Axial CT scans demonstrating intracranial

extension. (D) Coronal CT scans demonstrating intracranial extension. (E) Close-up frontal view before surgery.

(F) Direct vertical nasal incision following the nasal dermoid sinus cysts down to bone (note multiple cysts).

(G) Intraoperative view through a coronal (scalp) incision and after bifrontal craniotomy. The dermoid nasal sinus cyst

tract is followed toward the dura. (H) The intracranial cyst sinus tract extension required excision of involved dura. With

the mass excised and the dura repaired, an intraosseous dead space remains in the glabellar region of the frontal bones.

(I) The intraosseous dead space is closed with autogenous cranial bone shavings. The frontal bone was initially fixed with

direct wires, but the replaced bone tended to collapse. Miniplates were used to secure the bone in the anatomically

correct position. (From Posnick, J.C., Bortoluzzi, P., Armstrong, D.C., et al., Intracranial nasal dermoid sinus cyst:

computed tomographic scan findings and surgical results. Plast Reconstr Surg 1994; 93:745; with permission.)

86 J.C. Posnick, B.J. Costello / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 85–99

believed to be infrequent, although Wardinsky et al reported congenital anomalies in 41% oftheir patients with nasal dermoid sinus cysts.

On histologic examination, the dermoid sinus cyst contains ectodermal and mesodermal

derivatives. It is composed of a stratified squamous epithelial lining with specialized adnexal

tissues, which may include hair follicles, pilosebaceous glands, and smooth muscle. The presence

of adnexal dermal components distinguishes dermoid cysts from simple epidermoid cysts, and

unlike teratomas, they do not contain an endodermal component.

Intracranial extension of nasal dermoid sinus cysts is most frequently extraaxial, attached to

the dura, or confined within the leaves of the anterior falx (Fig. 1). Intraaxial extension intobrain parenchyma has been reported.

Earlier reports suggest that intracranial extension is a rare occurrence of just 1% or 2% of the

dermoid cysts that presenting in the nasal region. The more recent literature, however, indicates

a much higher prevalence of intracranial extension: Sessions reported a prevalence of 30%;

Wardinsky et al, 45%; Bradley, 10%; Clark et al, 26%; Naidich et al, 30%; Pensler et al, 19%;

Paller et al, 25%; and Posnick et al, 36%. These studies may indicate a high percentage of intra-

cranial extension that results from a referral bias to tertiary medical centers.

Computed tomographic scans have proved accurate in assessing intracranial extension ofnasal dermoid sinus cysts. Positive CT scan findings include subcutaneous midline cysts, bifid

Fig. 1 (continued )

87J.C. Posnick, B.J. Costello / Atlas Oral Maxillofacial Surg Clin N Am 10 (2002) 85–99

crista galli, and enlarged foramen cecum. MR imaging also can provide a clearer image of the

soft tissues and is of value in defining soft tissue masses and following the location of the sinus

tract.

Early recognition, accurate diagnosis, and prompt treatment of nasal dermoid sinus cysts

found to have intracranial extension are important. When nasal dermoid sinus cysts areuntreated, possible complications include bacterial meningitis, chemical meningitis, and brain

abscess.

To gain exposure for the removal of nasal dermoid sinus cysts, the authors favor a direct

vertical midline incision. If an intracranial extension is postulated, total excision of the lesion

requires a combined intracranial-extracranial approach through an additional coronal (scalp)

incision. Posnick et al documented the safety of carrying out a single-stage procedure when

intracranial extension is present.

Fig. 1 (continued )


In a previously published study, the presence of an intracranial extension of a nasal dermoid

sinus cyst was documented by Posnick et al in 36% (5 of 14) of (consecutive) patients with nasal

dermoid cysts. Although the authors believe the referral pattern may be biased toward the more

complicated problems, this rate concurs with the high incidence reported by others. The

authors’ patients varied in age from 4 to 48 months (mean, 25 months) at the time of referral.Most patients (three of five) with intracranial extension had lesions that were asymptomatic

masses (one had a chronic discharge and one recurrent bleeding). None had associated congen-

ital anomalies, unlike the patients in the study of Wardinsky et al, who reported a 41% incidence

of congenital anomalies. In accordance with the literature, most (four of five) of the authors’

patients’ lesions were located on the nasal dorsum. Contrary to the literature that describes

the sinus tract proceeding beneath the nasal bones and through the nasal septum into the skull

base, in three of the five patients, the tract penetrated the craniofacial skeleton at the level of the

nasal bones.The point of penetration through the nasofrontal suture occurred in one patient who had

multiple cysts in the nasofrontal area and nasal dorsum. This finding contrasts with the conten-

tion by Bartlett et al that a mass at or above the nasofrontal suture never penetrates the deeper

contiguous structure of involvement. An alternative embryologic explanation can be provided

to explain this occurrence: neuroectodermal derivatives may project through a patent fonticulus

frontonasalis rather than through the prenasal space.

Fig. 1 (continued )


Gliomas

Gliomas are composed of glial tissue that consists of non-nervous cellular elements of ner-

vous cells. Gliomas are not familial but are seen more frequently in men than in women (ratio,

3:2). Pensler et al reviewed a series of ten patients with gliomas who were treated over a 6-yeartime frame at a major pediatric referral center. Two of four of the intranasal lesions exhibited

intracranial extension. Six of ten of the gliomas were located extranasally. Extranasal gliomas

are usually located on the dorsum or just lateral to the bridge of the nose. They are noncompres-

sible lesions that do not transilluminate, and they appear as smooth, firm masses. The overlying

skin may be discolored or telangiectatic. One of six extracranial gliomas in this study group was

found to have intracranial extension. The intranasal gliomas are also noncompressible and

appear reddish, firm, and polyploid in character. Nasal obstruction and secondary septal distor-

tions with partial loss of olfaction may occur and depend on the size of the glioma. CT scanningor MR imaging or both should be carried out with contrast material to help clarify intracranial

extension. Differentiating between angiofibromas and other tumors and encephaloceles or der-

moids is important to ensure appropriate treatment.

Fig. 2. An 8-year-old girl raised in the Philippines was born with a large nasoethmoidal encephalocele that resulted in

severe distortions of the upper and midface structures (left greater than right). She had not previously undergone

treatment, and the mass affected vision, breathing, physical activities, and self-esteem. She was referred to the authors

and underwent a combined neurosurgical and craniofacial approach, including plication of the encephalocele and

immediate skeletal and soft-tissue reconstruction. The procedure was carried out through coronal (scalp) and direct

vertical nasal incisions and required multiple osteotomies, autogenous cranial grafting, and plate and screw fixation.

(A) Worm’s-eye view before surgery. (B) Three-dimensional CT scan (frontal view) of craniofacial region before surgery.

(C) Three-dimensional CT scan of craniofacial region indicating extent of encephalocele and secondary distortions of the

skeleton. (D) Three-dimensional CT scan of dura outline indicating extent of encephalocele. (E) Profile view before

surgery. (F) Midsagittal MR image indicating CNS soft tissues and extent of encephalocele. (G) Intraoperative bird’s-eye

view indicating extent of vertical excision over dorsum of nose with dissection of encephalocele down to bone.

(H) Intraoperative view through coronal incision after bifrontal and nasoethmoidal osteotomies to expose and then

plicate encephalocele. (I) Full-thickness autogenous cranial bone graft crafted to replace medial orbital rims. (J) View of

reconstructed orbitonasal regions. (K) Frontal view before surgery. (L) Frontal view 8 weeks after reconstruction just

before the patient’s return to the Philippines. Vertical elongation of central midface and nasal soft tissues remains.


The treatment of a glioma, like that of a dermoid sinus cyst, is surgical excision. It is recom-

mended that the lesions located intranasally be excised early in childhood when feasible to limit

the complications of infection and obstructive nasal breathing. Patients with cranial bone ero-

sion require an intracranial approach with immediate reconstruction that uses bone taken from

the cranium. Extranasal gliomas are excised through direct incisions.

Fig. 2 (continued )


Fig. 2 (continued )


Fig. 3. A boy born with a large nasofrontal encephalocele underwent three surgical procedures at another institution

in an attempt to plicate the encephalocele and reconstruct the fronto-orbitocranial base defects. Severe orbital

hypertelorism, orbital dystopia, and skull and cranial base defects remained, and the nasolacrimal apparatus functioned

poorly. He arrived for craniofacial reconstruction, which was carried out through a previous coronal (scalp) incision and

required multiple orbital, nasal, and frontal osteotomies, autogenous cranial bone grafting, and plate and screw fixation.

(A) Frontal view after initial procedures by another surgeon indicates residual orbital hypertelorism and dystopia.

(B) Two- and three-dimensional CT scans indicating extent of orbital dystopia/hypertelorism and skull defects.

(C) Right oblique view before surgery. (D) Right oblique view after reconstruction. (E) Left oblique view before

surgery. (F) Left oblique view after reconstruction. (G)Worm’s-eye view before surgery. (H)Worm’s-eye view after recon-

struction. (I) Intraoperative close-up view of cranio-orbital region before surgery. (J) Intraoperative close-up view of

cranio-orbital region after reconstruction. (K) Bird’s-eye view of anterior cranial vault before surgery. (L) Bird’s-eye

view of anterior cranial vault after reconstruction. (M) Comparison of three-dimensional CT scans of craniofacial region

before and after reconstruction. (N) Comparison of coronal CT slices through the midorbits before and after

reconstruction.


Encephaloceles

Encephaloceles may occur as isolated malformations or together with other anomalies as part

of various syndromes or associations. Encephaloceles can be classified as occipital, parietal, or

anterior (Figs. 2–4). Further subdivision of anterior encephaloceles may be made into (1) visible

Fig. 3 (continued )


(sincipital) and (2) not directly visible (basal). Approximately 75% of all encephaloceles occur in

the occipital region. Parietal encephaloceles account for approximately 10% to 14% of all ence-

phaloceles. Frontal encephaloceles aremuch less common than occipital encephaloceles in whites,

with the ratio being 1:6.

Fig. 3 (continued )


Frontonasal encephaloceles, encountered relatively rarely in occidental countries (1 in 35,000live births), are seen commonly in southeast Asia (1 in 5000 live births). Charoonsmith, in

Bangkok, has reported on a series of 310 individuals who presented with an encephalocele. He

categorizes frontoethmoidal encephalomeningoceles into three subgroups:

1. Nasofrontal encephalocele: The osseous defect is located in the bregmatic region, between

the two orbits, in the midline, at the root of the nose. The medial orbital walls are displaced

laterally.

2. Nasoethmoidal encephalocele: The osseous defect is between the frontal and ethmoid

bones. The herniated brain passes between the nasal bones and nasal cartilages with dis-

placement of the medial wall of the orbits.

3. Nasoorbital encephalocele: The frontal and nasal bones are normal. The herniated brain

passes through a defect in the medial orbital wall.

Nasofrontal and/or nasoethmoidal encephaloceles result in a variably increased distance be-

tween the frontal bones and the nasal bones with vertical elongation of the nose. The extent of

associated orbital hypertelorism varies. Not all hypertelorism necessarily requires correction.

Osteotomies of the orbits to correct hypertelorism may be necessary if the displacement is par-ticularly severe, however. There is no one reconstructive approach to these lesions. The design of

the osteotomies varies based on the dysmorphology seen. Some patients with severe displace-

ment of the orbital, ethmoid, nasal, and maxillary regions may benefit from a facial bipartition

procedure. These patients may require immediate reconstruction of the medial orbital walls

and nasal complex using autogenous bone grafts taken from the cranium. Other patients may

require only reshaping and reconstruction of the upper orbital rims and frontal bones.

When the encephalocele is associated with hydrocephalus, early ventriculoperitoneal shunt-

ing is essential. The initial neurosurgical management of the encephalocele should, in general,

Fig. 3 (continued )


go forward early in infancy. In most cases, repair of the osseous defect with autogenous cranial

graft is preferred at the time of neurosurgical plication of the encephalocele because it reinforces

the closure and limits the incidence of cerebrospinal fluid leakage and need for early reoperation

to manage this complication.

It has been the authors’ experience that the displacement of craniofacial skeletal structuresby the encephalocele does not progress over time unless untreated hydrocephalus expands

the encephalocele, resulting in progressive skeletal destruction. Definitive reconstruction of the

anterior cranial vault, orbits, and nasal bones is best postponed until 4 to 7 years of age, if at

all possible. By waiting until the child has attained a more adult level of upper face skeletal

maturity, the reconstruction is more definitive. Psychosocial considerations also support the

time frame of 4 to 7 years of age for the final cranioorbital procedure. When the procedure is

carried out at this age, the child may progress through grade school with a real chance for a

satisfactory body image and self-esteem. The functioning nasolacrimal apparatus is preservedand protected if possible, but it otherwise requires specific reconstruction.

Strabismus and amblyopia are best evaluated by a pediatric neuroophthalmologist early in

the child’s life. Eye patching and surgical correction may be necessary but must be evaluated

and treated before age 9 to 11 years to gain the maximum benefit.

The need for additional augmentation over the deficient nasal bones and orthognathic ( jaw

straightening) surgery in the teenage years should be anticipated for some patients. Waiting

for the upper and midfacial growth to be more complete allows for a more definitive reconstruc-

tion of the nasal complex if required. When necessary, the elective orthognathic surgery is

Fig. 4. A newborn with a large nasofrontal encephalocele underwent a combined neurosurgical and craniofacial

approach with encephalocele plication and soft-tissue reconstruction through a direct vertical nasal incision at 1 month

of age. At 2 months of age, he returned to the operating room for ventriculoperitoneal shunting and autogenous cranial

bone grafting to the frontonasal defect. He has maintained normal vision and has met his developmental milestones.

(A) View of child soon after birth. (B) Close-up profile view of child before surgery. (C) Profile view at 8 months of age,

after reconstruction. (D) Frontal view at 8 months of age, after reconstruction. Note hypertrophic scarring, which will

require soft-tissue revision.


carried out in conjunction with orthodontic treatment planned for completion at the time of

early skeletal maturity (approximately 13–15 years in girls and 15–17 years in boys). Facial scar

revision can be performed at any time after maturity of the scar tissue but is best delayed until

most growth has been completed in the region of concern.

Summary

The fronto-orbitonasal malformations of encephaloceles, dermoid sinus cysts, and gliomas re-present a continuum of neuroectodermal anomalies. The differentiation between them and other

similar-appearing lesions is essential for effective management to proceed. Obtaining a reliable

history, completing a careful physical examination, and obtaining accurate radiographic

documentation represent the first steps. Establishing the timing, staging, and specific surgical tech-

niques formanagement of a fronto-orbitonasal encephalocele remains asmuch an art as a science.

Fig. 4 (continued )


Suggested reading

Nasal dermoid sinus cysts

Bartlett SP, Lin KY, Grossman R, Katowitz J. The surgical management of the orbitofacial dermoids in the pediatric

patient. Plast Reconstr Surg 1993;91:1208–15.

Clark WD, Bailey BJ, Stiernberg CM. Nasal dermoid with intracranial involvement. Otolaryngol Head Neck Surg

1985;93:102–4.

Crawford JK, Webster JP. Congenital dermoid cysts of the nose. Plast Reconstr Surg 1952; 9:235.

Naidich TP, Bauer BS, McLone DG, et al. Nasal dermoid sinuses and cysts. Acta Radiol 1986;369(suppl):322–4.

Nevares RL, Mulliken JB, Robb RM. Ocular dermoids. Plast Reconstr Surg 1988;82:959–64.

Paller AS, Pensler JM, Tomita T. Nasal midline masses in infants and children: dermoids, encephaloceles, and gliomas.

Arch Dermatol 1991;127:362–6.

Pensler JM, Bauer BS, Naidich TP. Craniofacial dermoids. Plast Reconstr Surg 1988; 82:953–8.

Posnick JC, Bortoluzzi P, Armstrong DC. Nasal dermoid sinus cysts: an unusual presentation, computed tomographic

scan findings, and surgical results. Ann Plast Surg 1994;32:519–23.

Posnick JC, Bortoluzzi P, Armstrong DC, Drake JM. Intracranial nasal dermoid sinus cysts: computed tomographic

scan findings and surgical results. Plast Reconstr Surg 1994; 93:755–6.

Sessions RB. Nasal dermal sinuses: new concepts and explanations. Laryngoscope 1982; 92(Suppl 29):1.

Wardinsky TD, Pagon RA, Kropp RJ, et al. Nasal dermoid sinus cysts: association with intracranial extension and

multiple malformations. Cleft Palate Craniofac J 1991;28:87–95.

Glioma

Pensler JM, Ivescu AS, Ciletti SJ, et al. Craniofacial gliomas. Plast Reconstr Surg 1996;98:27–30.

Smith KR, Schwartz HG, Luse SA, et al. Nasal gliomas: a report of five cases with electron microscopy of one.

J Neurosurg 1963;20:968.

Walker EA, Resler DR. Nasal glioma. Laryngoscope 1963;73:93.

Encephalocele

Charoonsmith T. Review of 310 patients with frontoethmoidal encephalomeningocele with reference to plastic re-

construction.: Transactions of the 8th International Congress of Plastic Surgery, Montreal, 1983. P. 314–317.

Charoonsmith T, Suwanwela C. Frontoethmoidal encephalomeningocele with special reference to plastic reconstruction.

Clin Plast Surg 1974;1:27–47.

Cohen MM, Lemire RJ. Syndromes with cephaloceles. Teratology 1982;25:161–172.

David DJ: Cephaloceles: classification, pathology, and management. A review. J Craniofac Surg 1993; 4:192–202.

Gorlin RJ, Cohen MM, Levin LS: Syndromes of the head and neck. 3rd ed. New York: Oxford University Press, 1990

Jackson IT, Tanner NSB, Hide TAH. Frontonasal encephalocele: long nose hypertelorism. Ann Plast Surg 1983;2:

490–500.

MacFarlane R, Ritka JT, Armstrong D, Phillips J, Posnick JC, et al: Encephaloceles of the anterior cranial fossa.

Pediatric Neurosurgery 1995: 23: pp 148–158.

Posnick JC: Dermoids, Gliomas and Encephaloceles: Evaluation and Treatment. Craniofacial and Maxillofacial Surgery

in Children and Young Adults (Posnick JC, ed). W.B. Saunders Co., Philadelphia, 2000, Chap 25: pp 531–563.

Suwanwela C. Geographic distribution of frontoethmoidal encephalomeningocele. Br J Prev Soc Med 1972; 26:193–8.

Suwanwela C, Sukabote C, Suwanwela N. Frontoethmoidal encephalomeningocele. Surgery 1971; 69:617–25.

Suwanwela C, Suwanwela N. A morphological classification of sincipital encephalomeningoceles. J Neurosurg 1972;

36:201–11.


dermoid cysts, gliomas, and encephaloceles evaluation and treatment

Documents