Dermoid cyst

View Key Images

Diagnosis Definition

Dermoids are benign, ectoderm-lined inclusion cysts that can contain hair, sebaceous and sweat glands, and squamous epithelium
Most are congenital but they can also be iatrogenic or traumatic from puncture wounds
They are typically slowly expanding, unilocular, cystic masses with mild symptoms
Only 7% of dermoid cysts occur in the head and neck, with the most reported common locations being the lateral eyebrow region and the floor of the mouth; in addition, many are small but palpable superficial lesions embedded in the skin and subcutaneous tissue

Imaging Findings

Although unilocular, dermoid cysts may have internal septations and/or lipid material floating like supernatant “oil on water” over heavier proteinaceous debris
The imaging appearance on CT and MRI is variable, ranging from homogeneous fluid to heterogeneous attenuation/signal intensity due to keratinaceous and sebaceous content
The cyst wall is typically thin or non-perceptible but can become thick and radiologically visible; this thick lining can calcify and enhance
The sebaceous, lipid material in a dermoid has the attenuation and signal intensity of fat on both CT and MR images; a fat/fluid level is very suggestive of a dermoid cyst

Pearls

An inflammatory reaction can occur if a dermoid cyst is disrupted, and the cyst can recur if not completely excised
When the fat content coalesces into small globules within the fluid matrix, dermoid cysts have a so-called “sac of marbles” appearance

References

Koeller KK, Alamo L, Adair CF, et al. Congenital cystic masses of the neck: radiologic-pathologic correlation. RadioGraphics 1999; 19:121-146
Smirniotopoulos JG, Chiechi MV. Teratomas, dermoids, and epidermoids of the head and neck. RadioGraphics 1995; 15:1437-1455

Case-based learning.
Perfected.

Try MRI Online Premium for free.

Mastery Series video courses

High-yield cases

Expert case reviews

CME & SA-CME credits

Learn from world renowned radiologists anytime,
actice on real, high-yield cases with MRI Online Premium.

Learn from world renowned
radiologistsanytime, anywhere and practice on real, high-yield cases with MRI Online Premium.