Dermoid Cyst Removal
James W. Weightman, MD
PREOPERATIVE CONSIDERATIONS
On physical examination, determine whether the cystic lesion is a simple superficial dermoid cyst or a complex cyst with orbital or cranial involvement. If orbital or cranial involvement is suspected, imaging is recommended. Removal of a dermoid cyst is performed to prevent slow enlargement over time, remodeling of the underlying bone, and inflammation in the case of rupture. This procedure is often done around the time of the first birthday.
Physical Examination
Assess for:
Cyst mobility (a dermoid should feel rubbery and attached to bone at the base).
Location (mobility and location determine incision location).
Inflammation (if already ruptured, the cyst may be more difficult to dissect free).
Orbital involvement (proptosis or ptosis, assess whether cyst extends into orbit beyond the rim).
Differential diagnosis includes lipoma, hemangioma, encephalocele, meningocele.
The location of the cystic lesion guides the differential diagnosis.
Lateral orbital rim (frontozygomatic suture)—assess for mobility to rule out a “dumbbell” dermoid with orbital or intracranial extension.
Medial orbital rim (frontoethmoid or frontolacrimal sutures).
Assess mobility to rule out meningocele or meningoencephalocele and intracranial or intraorbital extension.
Determine if the mass expands with Valsalva or is pulsatile as this may indicate a meningocele or encephalocele.
Orbit.
Assess for proptosis.
Assess for ptosis.
Imaging
CT scan1:
Dermoid cysts are usually well-circumscribed lesions with a low-density lumen.
Dermoid cysts are often associated with bony remodeling.
Dermoid cysts may have fluid and fat levels internally with variable internal density in the lumen.
MRI:
T1 images typically are hypointense internally.
T2 images typically are hyperintense internally.
Ultrasound and color Doppler imaging (CDI):
Dermoid cysts generally have a smooth border with either an echogenic or hypoechogenic lumen.
CDI is useful to differentiate between vascular and cystic lesions.
CT scans are best suited for imaging bony abnormalities; while MRIs provide better images of soft tissues. Because MRIS do not use radiations, they are generally preferable in children.
SURGICAL PROCEDURE: EXCISIONAL BIOPSY OF DERMOID CYST
Simple cysts outside the skull are excised through an incision in the skin. If a cyst is more complex and extends deeply with attachments inside the orbit or extension to the brain, it may be necessary to consult otolaryngology, neurosurgery, or oculoplastics to assist with the cyst removal.
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