Objective: Neuronal migration disorders are usually, but not necessarily, demonstrated by magnetic resonance imaging. Preoperative suspicion of these anomalies in the presence of normal magnetic resonance studies has important practical implications. This study delineates some clinical features that permit early suspicion of focal cortical dysplasia localized in the central and precentral regions.
Design: In a retrospective case series, we studied the clinical presentation of four consecutive patients with normal preoperative magnetic resonance images in whom focal cortical dysplasia was found in the surgical specimen.
Setting: Patients were seen in three referral centers specializing in epilepsy surgery.
Patients: Four patients (three female), between the ages of 4 and 21 years, had intractable partial seizures leading to resective brain surgery.
Intervention: Three patients had corticectomies in the central (two patients) or frontal (one patient) regions. One underwent an en bloc resection of the central area after two unsuccessful corticectomies and cortical transection.
Results: Three patients presented with life-threatening focal motor status epilepticus necessitating intubation, and one had epilepsia partialis continua. All had had seizures previously, and the attacks progressed to intractability after 1 1/2 to 3 years. Surgery led to control of the seizures, but only two patients became seizure free (mean follow-up, 15.7 months). All but one developed a postoperative deficit, which eventually improved.
Conclusions: Focal cortical dysplasia should be suspected when life-threatening focal motor status epilepticus or epilepsia partialis continua occur in children or young persons without another obvious cause. Normal magnetic resonance studies do not exclude neuronal migration disorders.