Bilateral Subdural Hygroma in a Case with Sylvian Arachnoid Cyst

Arachnoid cysts are congenital lesions arising from the arachnoid membrane. The incidence of arachnoid cysts in the general population is around 0.1% and their most common location is the middle fossa. Arachnoid cysts usually present during the childhood and are identified incidentally. When symptomatic, the most common presentations include headache and seizure. The popular treatment for this lesion is surgery. In this case report, we describe a 12 year-old boy with a middle cranial fossa arachnoid cyst presenting with progressive headache, and bilateral subdural hygroma following a trivial head trauma.