Secondary bilateral synchrony associated to a parasagittal tumor. Case report

A 32 years old woman who had postural limbic and primarily generalized tonic-clonic seizures since the age of 11 presented to us with a CT image strongly suggestive of a mesial meningioma near the right cingulum. Her ictal EEG pattern was characterized by regular 1.5-2.0 Hz sharp and slow wave complexes. A right craniotomy was performed under general anesthesia and intraoperative electroencephalographic and electrocorticographic recordings were obtained by means of scalp steel electrodes and modified cerebellar stimulation electrodes, respectively. These recordings demonstrated that surface spikes were often independent from the electrocorticographically recorded ones. Before tumor excision, electrical stimulation of the peritumoral mesial cortex resulted in an increase in the epileptic activity. The stimulation of the cavity left after tumor excision led to a prolonged electrographic seizure and neurophysiological procedures were stopped. Post-operatively, the patient has remained seizure free for 6 months and her EEG was normal. The pre-, intra- and postoperative findings in this case suggest that the gliotic peritumoral mesial cortex was at least involved in the epileptogenic process.