Ruptured intracranial dermoid

Findings

Fat density lesion within the pericavernous region in the region of Meckel’s cave extending inferiorly into the posterior fossa. Scattered lipid droplets throughout the subarachnoid space.

Differential diagnosis:
- Dermoid cyst
- Epidermoid cyst
- Craniopharyngioma
- Teratoma
- Lipoma


Diagnosis: Ruptured intracranial dermoid


Key points

Congenital inclusion cyst.
Epidemiology: Rare; <0.5% of primary intracranial tumors.
30-50 y/o.
Presentation (uncomplicated): HA (32%), Seizure (30%), rarely with DI, hypopituitarism, visual defects.
Benign, slow growing.
Rare malignant transformation into SCCa.
Increased risk of rupture with increased size.
Significant M&M with rupture: chemical meningitis, seizures, coma, vasospasm, etc.
Fat density distinguishes from epidermoid (usually CSF density).
Scattered lipid droplets in subarachnoid/ventricles with rupture.
20 % have capsular calcium.
Most supratentorial, midline or near midline.
Other sites: spine, orbit.