Intracranial Dermoids:
Most dermoid tumors have signal intensity characteristics similar to fat—that is, they are hyperintense on T1-weighted images and hypointense on T2-weighted images. Fat-suppression techniques may be helpful in confirming the presence of fat in the lesion. Centrally, dermoid tumors may appear inhomogeneous due to the presence of hair follicles, calcifications, and cellular debris.Rupture of a dermoid tumor can result in fat droplets in the subarachnoid spaces or ventricles.
Spinal Dermoids:
The most frequent site of these tumors is in an extramedullary location; a few may lie in the substance of the cord itself. Complications of the cyst include secondary infection, particularly when associated witha dermal sinus. Rarely these lead to chemical meningitis from the cholesterol-laden keratin released in the subarachnoid space from a ruptured cyst leading to a foreign body type of reaction.
Presacral Dermoid:
A unilocular cystic mass located at or near the midline, with signal intensity similar to that of fat, is highly suggestive of a dermoid tumor.
Submitted by Dr MGK Murthy (Elbit Medical Diagnostics)
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