[Multiseptated arachnoid cyst treated with fenestration after valvular insufficiency in an adult. ]

Treatment of symptomatic arachnoid cysts is based on two procedures: cyst fenestration versus derivation of CSF. Multiseptated cysts represent a very special group. We present the case of a 75 year old woman with a symptomatic multiseptated arachnoid cyst, developing subacute bleeding in one of the cavities. Final diagnosis was obtained after MRI. CSF derivation became insufficient with clear improvement after fenestration and communication to subarachnoid space.