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Nasal dermoid cyst: two cases.

An 8-month-old infant was referred for recent enlargement of the nasal dorsum. Physical examination revealed a large cyst overlying the dorsum of the nose with a pit immediately below it. No drainage was evoked upon compression of the mass. Magnetic resonance imaging (MRI) confirmed the diagnosis of a 5-mm nasal dermoid cyst with an enhancing sinus tract into the foramen cecum (figure 1, A). Computed tomography (CT) with fine coronal cuts through the anterior skull base revealed no intracranial extension. Because of the external pit, the cyst was removed via a dorsal incision. Postoperatively, the child did well without recurrence 6 months after surgery.

[FIGURE 1 OMITTED]

In contrast, a 30-month-old toddler with a history of a pit on the tip of her nose presented for evaluation. On examination, the nasal dorsum was observed to be very wide and the nasal bones splayed outward by what was likely to be a nasal dermoid cyst. MRI confirmed a midline dermoid cyst with a large intranasal component under the nasal bones, a patent foramen cecum, and no intracranial component (figure 1, B).

The second patient underwent an external rhinoplasty approach to remove the cyst. After removal of a small external component of the cyst, an internal component was visualized and a central osteotomy was performed. When the nasal bones were split, extensive amounts of hair and proteinaceous material drained out of the site (figure 2, A), consistent with a nasal dermoid cyst. The entire cyst was removed through the osteotomy to reveal the closed dura pulsating at the base of the foramen cecum (figure 2, B). No intracranial extension was identified.

These cases illustrate the significance of nasal dermold cysts as the most common congenital midline nasal masses. They account for 1 to 3% of all dermoid cysts and 4 to 12% of all head and neck dermoid cysts) Twenty to 45% of these lesions will have an intracranial connection. (2,3) This frequency is higher if other congenital anomalies are present? Nasal dermoid cysts have been associated with cleft defects, aural atresia, or hydrocephalus in up to 41% of cases. (2) Other craniofacial abnormalities including craniosynostosis, hemifacial microsomia, lacrimal duct cysts, and hypertelorism have also been described in association with nasal dermoid cysts. (3)

[FIGURE 2 OMITTED]

Nasal dermoid cysts consist of both ectodermal and mesodermal elements, including hair follicles and sebaceous glands. Like nasal gliomas and encephaloceles, nasal dermoids result from embryologic defects in the anterior skull base. The lesion may be extranasal, intranasal, or both. Most often, the lesion is confined superficially. If intracranial extension is present, it classically occurs through the foramen cecum or cribiform plate and attaches extradurally to the falx cerebri. (4)

Most nasal dermoid cysts are diagnosed within the first 3 years of life. The mass is usually slow growing, with or without an associated midline pit anywhere along the nasal dorsum. About one-half of all nasal dermoid cysts are associated with a pit or sinus. They may go unnoticed until an infection occurs, resulting in rapid enlargement. On examination, the mass is typically firm and noncompressible and does not transilluminate. Protruding hair or extruding sebum from the pit is highly suggestive of the diagnosis.

MRI is the most accurate and cost-effective method of establishing a diagnosis. (5) Not only is it more sensitive and specific than CT, but it is also superior for visualizing soft tissue and evaluating intracranial extension. On T1-weighted MRI images, a nasal dermoid cyst appears as a hyperintense lesion. CT may be useful for visualizing bony defects of the anterior skull base.

Surgical removal remains the treatment of choice to prevent complications, such as infection or bony nasal remodeling. A number of approaches have been described for excision, including lateral rhinotomy or a midline vertical, transverse, or midbrow incision. A midline vertical incision is the most popular and straightforward technique, but any of the incisions can achieve adequate exposure with good cosmetic results. (3) If the nasal structure has been altered, a cartilage graft may be necessary. If an intracranial component is seen on MRI, a combined approach with craniotomy is preferred. Without treatment, the lesion will typically continue to grow and will erode the underlying bone.

Intracranial extension increases the risk of meningitis, cavernous sinus thrombosis, or other CNS complications from infection. If the dermal elements are not completely removed during surgery, the recurrence rate is as high as 50 to 100%. (5,6) With complete excision, however, prognosis is good. Regardless, facial scarring or nasal deformities can persist.

References

(1.) Sessions RB. Nasal dermal sinuses--new concepts and explanations. Laryngoscope 1982;92(8 Pt 2 Supp129):1-28.

(2.) Denoyelle F, Ducroz V, Roger G, Garabedian EN. Nasal dermoid sinus cysts in children. Laryngoscope 1997;107(6):795-800.

(3.) 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(1):87-95.

(4.) Zapata S, Kearns DB. Nasal dermoids. Curr Opin Otolaryngol Head Neck Surg 2006;14(6):406-11.

(5.) Bloom DC, Carvalho DS, Dory C, et al. Imaging and surgical approach of nasal dermoids. Int J Pediatr Otorhinolaryngol 2002: 62(2):111-22.

(6.) Carroll CM, Gaffney R, McShane D. Congenital nasal dermoids in children. Ir J Med Sci 1997;166(3):149-51.

Esther Garazi, BS; Soham Roy, MD

From the Department of Otolaryngology, Miller School of Medicine, University of Miami, Florida.
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Title Annotation:PEDIATRIC OTOLARYNGOLOGY CLINIC
Author:Garazi, Esther; Roy, Soham
Publication:Ear, Nose and Throat Journal
Article Type:Case study
Geographic Code:1U5FL
Date:Apr 1, 2009
Words:896
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