MRI features of an intracranial dermoid cyst ruptured within the subarachnoid spaces with aseptic chemical meningitis.

Cyst rupture within the subarachnoid spaces of the ventricular system is the most common complication. The best diagnostic is fat-like droplets in cortical sulci, subarachnoid cisterns and ventricles. The rupture within the ventricles gives a fat-fluid level.