PERICOLLATERAL CORTICAL DYSPLASIA: AN ETIOLOGY FOR REFRACTORY TEMPORAL LOBE EPILEPSY
Cukiert A, Burattini JA, Mariani PP, Camara RB, Seda L, Baldauf CM, Argentoni-Baldochi M, Baise-Zung C, Forster CR, Mello VA.
Department of Neurology and Neurosurgery, Epilepsy Surgery Program, Hospital Brigadeiro and Clinica de Epilepsia de Sao Paulo, Sao Paulo SP, Brazil
Cortical dysplasia is an important etiology of refractory epilepsy, especially in the pediatric population. We describe a distinct type of focal cortical dysplasia which is centered on the collateral fissure and associated to refractory temporal lobe epilepsy.
Five patients with refractory temporal lobe epilepsy were studied. Age ranged from 3 to 25 years (mean=18 years), age at the beginning of seizures from 2 to 14 years (mean= 8 years) and seizure frequency from 3 to 10 / week (mean= 5 seizures/week). All patients had simple (vegetative in 4 and cephalic in one) and complex partial seizures. Interictal EEG showed unilateral temporal lobe spiking in 4 and bilateral discharges in one patient. No patient was submitted to video-EEG monitoring. MRI disclosed dysplastic lesions in all patients. These lesions were spread around the collateral fissure, occupying both the parahippocampal and fusiform gyri. In four patients, imaging findings suggestive of ipsolateral mesial temporal sclerosis were also noted. In one patient, the hippocampus looked normal (visual analysis). All patients were submitted to a cortico-amygdalo-hippocampectomy at the side of the MRI-defined lesion.
All patients were rendered seizure-free after surgery. Pathological examination showed cortical dysplasia and mesial temporal sclerosis in all patients, including the patient with a normal looking hippocaqmpus on MRI.
Pericollateral cortical dysplasia seems to be a very specific etiology of refractory temporal lobe epilepsy with many features of classical mesial temporal epilepsy. It is usually associated to mesial temporal sclerosis and surgical outcome is probably similar (or better) to that obtained in patients with mesial temporal sclerosis alone.