Patient Presentation
A 24-month-old male came to clinic for his health supervision visit. He was overall well but his father noted that he had a “bump” on the side of his forehead. He had noted it sometime in the past couple of months and it hadn’t grown appreciably or had changed in any significant way. It was not bothering the patient. The past medical history was non-contributory.
The pertinent physical exam showed an energetic infant with growth parameters in the 75-90% and trending appropriately. Along the right lateral coronal suture area of the right lateral brow there was a non-mobile, 1.5-2 cm firm lesion without overlying erythema or edema. It was non-pulsatile and did not transilluminate. There were no other lesions. His examination was otherwise unremarkable.
The diagnosis of a possible dermoid cyst was made. The patient was referred to neurosurgery and radiologic evaluation of a magnetic resonance imaging study revealed a dermoid cyst. After discussion with the family the lesion was excised and diagnosis of a simple dermoid cyst was confirmed. The patient had no post-operative complications.
Figure 140
– Coronal (above) and axial (below) CT with contrast of the orbits show a right superolateral rounded low density mass that is not causing any bone erosion.
Discussion
“Dermoid cysts [DC] are benign cutaneous [cystic] neoplasms that originate from entrapment of ectodermal and mesodermal elements within embryonic fusion planes….” They are lined with dermal and epidermal components which can include hair, keratin and lipid debris. These are usually what are referred to as congenital DC. There can also be teratoma-type DC which are found in the ovaries and testes. There can also be acquired DC due to “…forced implantation of skin into deeper structures by trauma.” For this case DC will refer to congenital DC.
DC can be located anywhere in the body, but are especially common on the head and neck. Lateral brow “…originating from the frontozygomatic suture are the most common….” Other common head locations are the nasoglabellar and periorbital areas.
They present usually as painless, palpable subcutaneous masses. They are slow growing, do not transilluminate and should not change with Valsalva maneuver. If the size does change, then the DC is likely to have extension into the intracranial space.
Treatment is excision with or without pre-operative radiological imaging depending on patient age and location.
The differential diagnosis of other head and scalp lesions includes:
- Bone cysts, primary bone tumors and metastasis
- Craniosynostosis
- Dermatological problems such as lipomas
- Hemangiomas
- Hematoma
- Infection
- Langerhans cell histiocytosis
- Lymph nodes
- Myofibromas
- Encephalocoeles
- Meningocoele
Learning Point
DC are one of the most common head lesions in the pediatric population accounting for up to 60% of lesions in some studies. DC are benign and can be simple subcutaneous lesions but they can have complications including disfigurement due to changes in the soft tissue and bone in the area of the lesion, and infection. Intracranial extension can risk meningitis or intracranial abscess.
DC located in the nasoglabellar region are much more likely to have intracranial extension or bony erosion than other locations. A metaanalysis found a rate of 19.9% but other papers list as high as 57% risk of intracranial extension for nasoglabellar DC. DC in other locations usually have lower risk of intracranial extension. One 2020 series of 655 total pediatric patients treated surgically found the following results:
| Location | Total Cases (N) |
Intracranial Extension (N, %) |
|---|---|---|
| Lateral Brow | 362 | 1, 0.27% |
| Midline Nasal | 87 | 10, 11.4% |
| Frontal or Anterior Fontanelle | 38 | 14, 36.8% |
| Occipital | 43 | 7, 16.3% |
| Temporal | 37 | 6, 16.2% |
| Other locations | 88 | 0, 0 % |
Questions for Further Discussion
1. What is your process for evaluation of lymphadenopathy? A review can be found here
2. What are types of craniosynostosis? A review can be found here
3. How are potential dermoid cysts evaluated in your location?
Related Cases
- Disease: Dermoid Cyst | Bone Diseases
- Symptom/Presentation: Mass or Swelling
- Age: Toddler
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for this topic: Bone Diseases
To view current news articles on this topic check Google News.
To view images related to this topic check Google Images.
To view videos related to this topic check YouTube Videos.
Van Kouwenberg E, Kanth AM, Mountziaris P, Adetayo OA. Cranial Erosion Associated With Non-Midline Dermoid Cysts in the Pediatric Population. J Craniofac Surg. 2019;30(6):1760-1763. doi:10.1097/SCS.0000000000005317
Overland J, Hall C, Holmes A, Burge J. Risk of Intracranial Extension of Craniofacial Dermoid Cysts. Plast Reconstr Surg. 2020;145(4):779e-787e. doi:10.1097/PRS.0000000000006655
Serrallach BL, Orman G, Hicks MJ, Desai N, Kralik S, Huisman TA. Conventional and advanced MR imaging findings in a cohort of pathology-proven dermoid cysts of the pediatric scalp and skull. Neuroradiol J. 2022;35(4):497-503. doi:10.1177/19714009211059120
Author
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa
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