Coexistence of epileptic nocturnal wanderings and an arachnoid cyst.

Episodic nocturnal wanderings (ENWs) have rarely been associated with gross abnormalities of brain structures. We describe the case of a patient with ENWs in coexistence with an arachnoid cyst (AC). The patient was a 15-year-old boy who presented with nocturnal attacks characterized by complex motor behaviors. An MRI revealed a left temporal cyst and a SPECT Tc99 scan showed left temporal hypoperfusion and bilateral frontal hyperperfusion, more evident on the right side. During an all-night polysomnographic recording with audiovisual monitoring, dystonic posture followed by sleepwalking-like behavior was documented. The sleepwalking-like behavior was preceded by a spike discharge over the left frontocentral region with contralateral projection and secondary generalization during stage 2 sleep. Treatment with levetiracetam produced a striking remission of seizures. This supports a conservative management of an AC, considering that it may be an incidental finding. In epileptic patients, an AC may not necessarily be related to the location of the seizure focus.