Dermoid cyst of the posterior fossa.

Intracranial dermoid tumors represent a rare clinical entity accounting for 0.1-0.7% of all intracranial tumors. Their location in the posterior fossa is uncommon. We report a 16-year-old male patient who presented with clinical signs of increased intracranial pressure and cerebellar symptoms. The CT scan revealed a median cystic lesion of the fourth ventricle causing an active triventicular hydrocephalus. The MRI showed a median well shaped cystic lesion, of low signal intensity compared to the CSF, with capsular contrast enhancement. He underwent endoscopic third ventriculostomy before subtotal removal of the lesion. The postoperative course was uneventful, and the histological diagnosis was a dermoid cyst. Through this observation, we aim to discuss the clinical, and radiological aspects of the posterior fossa dermoid cyst, and to review the therapeutic strategies.