Middle fossa arachnoid cysts in association with subdural haematomas. A review and recommendations for management.

Subdural haematomas occur in association with arachnoid cysts. Six cases of subdural haematoma are reported in 18 patients with previously asymptomatic middle fossa arachnoid cysts. A review of this patient population and the literature in respect of pathogenesis and treatment of arachnoid cysts was made. Cysto-peritoneal shunt is recommended as the surgical treatment after evacuation of the haematoma. The aetiology of haematoma formation has not been conclusively described, but may partly result from a high pressure intracranial system with decreased compliance.