History
Dermoid cysts that are congenital and localized on the neck, head, or trunk are usually visible at birth. In some instances, careful medical examination may be necessary to identify a dermoid cyst. A tuft of hairs emanating from a midline nasal depression or nodule may represent a nasal dermoid cyst. [5] Unilateral upper eyelid swelling may be the first sign, with imaging studies demonstrating a soft tissue orbital dermoid cyst arising from the lacrimal gland. [6] Dermoid cysts are the most common orbital tumor of childhood. [7] An eyelid dermoid cyst attached to a tarsus may be evident as a firmly adherent nontender upper-eyelid nodule. [8] A dermoid cyst of the lower lid may be evident as a painless, gradually enlarging swelling of the lower eyelid. [9] Dermoid tumors in the medial canthal area may present as masses adherent to the lacrimal canaliculi. [10] Rarely, a dermoid cyst evident during the newborn period clinically appears, only to become evident years later with full-thickness bone erosion and transcranial extension. [11]
Intracranial, intraspinal, or intra-abdominal dermoid cysts may be suspected after specific or nonspecific neurologic or gynecologic symptoms occur. In these instances, imaging studies may help in distinguishing dermoid cysts from other tumors or organ malformations (see Imaging Studies). A congenital intracranial frontotemporal dermoid cyst may be first evident as a cutaneous fistula, although intracranial extension and cutaneous sinus tract formation are rarely seen with these dermoid cysts. [12]
Physical Examination
Dermoid cysts can appear as cutaneous cysts on the head, as cysts on the floor of the mouth or elsewhere in the head, within the parotid gland, [13] or as cysts in the testes or penis. They can be quite large. [14]
Specialists in various disciplines may consider dermoid cysts to be different entities.
Head and neck
Cutaneous cysts most commonly occur on the head (forehead), mainly around the eyes. They may be evident as a tadpole-shaped cyst on the eyebrow. [15] Occasionally, they occur on the neck or in a midline region. When on the head, dermoid cysts are often adherent to the periosteum. The usual diameter of the lesions is 1-4 cm.
In one study, 25 benign tumors on the forehead and brow of children and adolescents were successfully removed by means of endoscopic excision. Of these, 6 were classified as dermoid cysts. Dermoid cysts on the forehead and brow are known to cause pressure-related erosion of the underlying bony tissue, and surgical intervention may be helpful.
In 191 children treated for congenital cysts and fistulas of the neck in 1984-1999, 21 dermoid cysts were found. Periauricular fistulas and cystic hygromas were not included in this study. [16]
Occasionally, skin-related dermoid cysts are multiple and develop over periods as long as 20 years. In one unusual case, multiple subcutaneous dermoid cysts were present in the frontal region of a 41-year-old man, none with evident intracranial extension.
In many patients, dermoid cysts occur on the floor of the mouth or elsewhere in the mouth. [17, 18, 19, 20]
Because the term dermoid is frequently used in the literature, some authors believe that this term should be used for all congenital cysts on the floor of the mouth. Three subclasses of congenital mouth cysts are described in the literature: epidermoid (simple) cysts, dermoid (complex) cysts, and teratoid (complex) cysts. Most of these lesions occur in individuals aged 10-30 years. Only a few cases describe dermoid cysts of the mouth in newborns or children.
An unusual case of a carcinomatous transformation of a long-standing sublingual dermoid cyst has been described. [21]
Other rare dermoid cysts in the oral cavity are those on the tongue. [22, 23] As of early 2000, 17 patients with intralingual dermoid cysts are described in the English-language literature. All cases occurred in young patients. Magnetic resonance imaging (MRI) was helpful in establishing the differential diagnosis. Surgical excision corrected deglutition and speech problems in all of these patients.
Dermoid cysts in the eustachian tube are rare. [24] Only 12 patients have been described. In most cases reviewed, cysts affected female patients on the left side. MRI was useful in establishing the correct diagnosis and in selecting the surgical approach.
Reports of nasal dermoid cysts were recently published. Of 36 children with nasal dermoid sinus cysts that were treated from 1974-1994, 10 had only a midline cyst, 8 had only nasal pits, and 18 had combined cysts. Meningeal adherences have been found in only 2 patients. [25] Nasal dermoid cysts may be evident as a midline nasal pit, fistula, or infected mass from the glabella to nasal columella, sometimes as a midline nasal punctum at birth. [2]
Testes or penis
Dermoid cysts can occur in the testes or penis.
In a review of cystic testicular lesions in the pediatric population, dermoid cysts were noted. [26] Other diagnoses for these cysts include epidermoid cyst, prepubertal teratoma, juvenile granulosa cell tumor, cystic dysplasia of the rete testis, testicular cystic lymphangioma, simple cyst, and cystic degeneration after torsion. An understanding of potentially cystic testicular lesions in children leads to the best treatment choices and often to the preservation of a substantial portion of the affected testis.
Dermoid cysts in the penis are extremely rare. Tomasini et al [6] described the first in 1997. The patient was a young white male who had significant penile swelling for several months.
Spine and cranium
For neurosurgeons, dermoid cysts are associated with congenital cysts of the spine or intracranial cysts.
Several cases involve ruptured cysts and generalized subarachnoid and ventricular spread of the contents (mostly fatty masses). [27, 28, 29]
In some patients, spinal dermoid cysts, especially those connected to dermal sinus tract, lead to severe neurologic complications such as secondary spinal subdural abscesses caused by the spread of the infection in the dermoid cyst. Bilateral orbital abscesses were described as a result of an infected nasal dermoid cyst. [30]
Ovary
For gynecologists and general pathologists a dermoid cyst is primarily associated with a cystic tumor of the female ovary.
Cystic teratoma is a relatively rare tumor that most often occurs in females aged 15-40 years. A cystic teratoma consists of a thick leatherlike capsule that covers amorphous fatty masses and poorly to fully differentiated structures derived from the ectoderm. Most ovarian dermoid cysts contain skin and skin adnexa, including prominent sebaceous glands, hairs, and nails, but also teeth or eyes. Melanotic changes may also occur. Rare cases of multiple dermoid cysts of the omentum have been reported. [31] Dermoid cysts of the ovary are usually benign and easy to remove.
Malignant melanomas may originate from melanocytes in ovarian cystic teratomas. Two new cases and 17 older cases in the literature (reported from 1903-1995) are described and were critically reviewed. The present authors found 17 additional cases of benign and malignant melanotic ovarian lesions that were not associated with a dermoid cyst, including 4 melanomas, 3 benign nevi, 5 benign melanosis, and 4 benign and malignant retinal anlage tumors. The extremely rare primary ovarian melanoma was differentiated from the more common melanoma metastatic cyst of the ovary by its unilaterality, the presence of junctional change, and detailed history taking and physical examination, the findings of which excluded other primary sites. [32]
Three patients with metastasizing squamous cell carcinoma from a dermoid cyst of the ovary are described. [33] Malignant transformation in a dermoid cyst is a rare complication and mainly occurs in older individuals. Although the prognosis is poor, aggressive therapy may result in long-term remission.
Complications
Several possible complications of spontaneous or posttraumatic rupture and surgical procedures have been described. In patients with a ruptured spinal dermoid cyst, fatty droplets can disseminate in the cerebrospinal fluid or in a dilated central canal of the spinal cord. In other patients, subarachnoid and ventricular fat dissemination can occur after the cerebellopontine angle dermoid cyst is resected. Spinal subdural abscesses are a possible complication because of the bacterial infection of spinal dermoid cysts in a dermal sinus tract. A ruptured intracranial dermoid cyst be an incidental finding on an MRI performed for other purposes or because of a persistent headache. [34]
Pay special attention to intralingual dermoid cysts because deglutition and speech problems may occur.
Nasal dermoid cysts in a nasal tip location are rare, but they may produce social and psychologic problems in children. [35]
Malignant transformation is an unusual complication that may occur in patients with long-standing dermoid cysts. Carcinomatous transformation to a squamous cell carcinoma is described in sublingual and intra-abdominal dermoid cysts, most often dermoid cysts of the ovary. Metastatic malignant melanomas arising from dermoid cysts have been reported in the literature.
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Dermoid cyst in an unusual location. Courtesy of DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/lesions/d-cyst.jpg).
