Spontaneous chronic subdural hematoma associated with arachnoid cyst in children and young adults

Arachnoid cysts are clear, colorless fluid-filled cysts that arise during brain and skull development from the splitting of the arachnoid membrane. Chronic subdural hematoma (CSDH) is an encapsulated collection of old blood, mostly or totally liquefied and located between the dura mater and the arachnoid mater. Trauma is an important factor in the development of CSDH. Here, we report four patients, previously asymptomatic, revealing CSDH with AC on computed tomography (CT) and magnetic resonance imaging (MRI) of the brain. All patients underwent craniotomy with evacuation of hematoma and resection of the cystic membrane that was then connected to the basal cistern under the operating microscope. Postoperatively, all patients were symptom-free. Presentation of an AC with chronic subdural hematoma in the absence of preceding head trauma is considered to be rare in children and young adults.