Dermoid cyst mimicking hematoma in the posterior fossa.

Intracranial dermoid cysts are usually reported to be associated with long lasting or waxing-waning symptoms. Computer tomography (CT) scans usually depict such neoplasms as well-defined areas of low density. This report is about a case of a dermoid cyst, the acute clinical features and CT hyperdensity of which mimicked a hematoma in the posterior fossa. The association of acute onset with CT hyperdensity makes this case of dermoid cyst very unusual.