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Orbital Dermoid
Case Detail
| Anatomy: Neck-Face |
 Joseph Junewick, MD FACR |
| Diagnostic Category: Neoplasia Benign |
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| Created: over 7 years ago |
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| Updated: over 7 years ago |
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| Tags:
PEDS
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| Modality/Study Types:
CT
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Activities:  PDF  ImageJA |
History
14 month old with painless, slowly growing lateral left orbital mass.
Case Images
Diagnosis
Orbital Dermoid
Findings
CT – Axial and coronal reformat demonstrate small well-circumscribed ovoid lesion along the lateral margin of the left orbit measuring -10 Hounsfield units.
Discussion
A dermoid is a benign tumor composed of tissue derived from ectoderm and mesoderm. Dermoids may be solid or cystic, although cystic lesions predominate. Around the orbit, these tumors usually arise along fetal cleavage planes and as such are very common near cranial sutures.
Most are extraconal; approximately 60% are encountered in the supero-temporal quandrant and 25% are seen in the supero-nasal quadrant. Occasionally lesions are retrobulbar and cause proptosis. Rupture can incite a fairly dramatic inflammatory response mimicking cellulitis. Epibulbar dermoid cysts are frequently seen in Goldenhar syndrome.
On CT, dermoids are well defined uniformly low density lesions; when Hounsfield units are negative, the diagnosis is secured. Often the adjacent bone is gently remodeled or the cortex is scalloped. The capsule/epithelial lining may show some enhancement. On MR, the appearance of dermoids varies depending on the amount of fat content. Generally, there is intermediate to high signal on T1 and high signal on T2 sequences.
Reference
Chung EM, Murphey MD, Specht CS, Cube R, Smirniotopoulos J. From the Archives of the AFIP Pediatric Orbit Tumors and Tumorlike Lesions: Osseous Lesions of the Orbit. Radiographics (2008); 28:1193-1214.
Contributor
John Quick, MD