Newswise — Dermoids are unusual neoplasms often found in childhood, but subject to confusion during the diagnosis. This benign neoplasm is derived from the ectoderm and mesoderm, the two outer layers of the embryo, and can contain such tissue as hair follicles, teeth, and other prenatal material. Although they may be seen at birth, age at presentation can vary widely and sudden changes in size can make diagnosis more difficult. Approximately seven percent of all dermoids occur in the head and neck with the most common locations reported as periorbital (near the bony cavity containing the eyeball), nasal, beneath the chin, and above the sternum. These varied locations of dermoid growths may lead caregivers to bring their pediatric patients to a wide variety of practitioners including: pediatric surgeons, otolaryngologists, plastic surgeons, ophthalmologists, neurosurgeons, and primary care physicians, all needing to be keenly aware of diagnostic techniques and treatment options for these suspicious looking growths.
A team of researchers from the Mayo Clinic has defined these neoplasms through their experience with the presentation, diagnosis, and treatment of pediatric dermoid cysts of the head and neck. The authors of "Pediatric Dermoids of the Head and Neck" are Shepherd G. Pryor MD, Jean E. Lewis MD, Amy Weaver, and Laura J. Orvidas MD, all from the Department of Otorhinolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN. Their findings will be presented September 23, 2003, at the American Academy of Otolaryngology-Head and Neck Surgery Foundation http://www.entnet.org Annual Meeting and OTO EXPO, being held September 21-24, 2003, at the Orange County Convention Center, Orlando, FL.
Methodology: After obtaining IRB approval, the Mayo Clinic Diagnostic Information Recording System identified all patients younger than 18 years of age who were diagnosed with a dermoid of the head and neck between 1980 and 2002. Only those children who underwent surgical treatment were included in the study and had their medical histories reviewed for demographic information, diagnostic techniques, treatment, and outcomes. Tissue specimens were available in all patients and tumor histology was reviewed and confirmed by a pathologist.
Results: Forty-seven children were included in this study (19 boys [40 percent] and 28 girls [60 percent]). The age at presentation ranged from birth to 17 years (mean 36 months, median 12 months). The most common presentation was a palpable mass (n=47, 100 percent). Other presentations included a noticeable size change (n=31 [66 percent]), fixed position (n=26 [55.3 percent]), firm consistency (n=13 [27.7 percent]), and cystic consistency (n=10 [21.3 percent]). Two patients [4.3 percent] presented with a prior history of local infection presenting as a draining sinus. None presented with intracranial infection or meningitis. Two patients presented with pain in the area of the palpable mass and two had a prior history of trauma to the site. Two patients percent had visual symptoms defined as ptosis. All 47 patients were grouped into five defined anatomic sites: periorbital (most common, 29 patients), neck (nine patients), head not neck (four patients), nasal (three patients), and ear (two patients). Twenty-eight patients underwent preoperative imaging, including computed tomography (CT), ultrasound, plain radiographs, and MRI. Of those patients, two (of the 28) received both MRI and CT.
Treatment was site dependent with most lesions removed at the site by either direct excision or endoscopic removal. Overall follow-up in all patients was 9.6 to 77.6 months (mean 50.6, median 36.7) and recurrence was rare with only a single patient experiencing recurrence. With the exception of one patient with anosmia, no other complications occurred.
Conclusions: Dermoid cysts are thought to be of the congenital inclusion type, forming along the lines of embryologic fusion and containing both dermal and epidermal derivatives. The differential diagnosis, based on location, includes epidermal inclusion cysts, glioma, meningomyelocele, meningoencephalocele, teratoma, teratoid cyst, thyroglossal duct cyst, brachial cleft cyst, and benign lymphadenopathy. Although history and physical exam are essential components to the workup and evaluation of these neoplasms, dermoid cysts must be identified through a pathologic diagnosis. Congenital inclusion dermoid cysts are further broken down into four subdivisions:
"¢ Group 1 cysts develop in the periorbital region, appearing along the naso-optic groove between the maxillary and mandibular processes during embryonal closure. The periorbital region is the most commonly reported site for dermoid cysts of the head and neck, with 62 percent of patients in this study having a dermoid cyst in that region. The researchers found that complete excision via direct or endoscopic approach should prevent recurrence as demonstrated in this series. "¢ Group 2 cysts develop over the dorsum of the nose and are thought to develop during the bone formation in the frontonasal plate. These cysts may be located from the subcutaneous layer to the bony or cartilaginous nasal septum, within the sphenoid sinus or ethmoid sinus, and anterior cranial fossa, and represent approximately eight percent to 12.6 percent of all dermoid cysts of the head and neck. In this research, nasal dermoid cysts accounted for six percent of lesions identified, presenting as a swelling over the nasal dorsum and possibly associated with a sinus opening or punctum. Intermittent discharge of sebaceous material and recurrent infection is common. In this research, one third of this group's nasal dermoids extended intracranially, necessitating a thorough preoperative radiographic evaluation including CT and MRI.
"¢ Group 3 cysts are found below the chin, the floor of mouth, and the region of fusion of the first and second branchial arches in the midline. These may assume significant importance as they enlarge and can impair both deglutition and speech, or pose a critical risk to the airway. None of the subjects had a cyst in this group.
"¢ Group 4 cysts are formed at the mid-ventral and mid-dorsal fusion in the suprasternal, thyroidal, and suboccipital regions, where they are typically confused with thyroglossal duct cysts or thyroid neoplasms, suprasternal masses and enlarged lymph nodes, or meningoencephalocele. These have been reported as occurring in five percent to 15 percent of patients. One in five of the dermoids found in this study were in this category. CT or MRI scanning but this may be beneficial in select patients, but diagnosis in this group is aided by ultrasound (seven of nine study participants). These lesions were all successfully removed via direct excision.
Dermoids are unusual neoplasms which often present in childhood, with the orbit being the most common area affected in the head and neck region. Histologically dermoid tumor must contain two germ cell layers and require pathological confirmation to establish diagnosis. Imaging studies are essential to rule out both intracranial and intraorbital extension. Dermoid cysts are excised to prevent subsequent infection, establish pathologic diagnosis, and ameliorate a cosmetically deforming lesion. Recurrence is unusual with complete excision.
RSS