Combination of stereo-electroencephalography and electrocorticography to manage mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE): a case report.

INTRODUCTION: Mild malformation of cortical dysplasia with oligodendroglial hyperplasia and epilepsy (MOGHE) is a rare form of cortical malformation pathologically characterized by oligodendroglial proliferation and hypomyelination. CASE PRESENTATION: Herein, we describe a 25-year-old patient with MOGHE in the right temporal lobe who has suffered from refractory epilepsy since 4 months of age, highlighting a remarkably delayed diagnosis. Magnetic resonance imaging (MRI) suggested cortical thickening and an abnormally low gyrification index in the frontotemporal region. A positron emission tomography (PET) scan reported right mesial temporal hypometabolism. The EEG findings revealed bilateral paroxysms of high-amplitude slow spike-waves with a frequency of 2.5-3 per second in the awake state and 1-1.5 per second in sleep, with a normal posterior dominant rhythm. The SEEG depicted involvement of the middle and inferior frontal gyri, temporal pole, medial temporal, and orbitofrontal regions, reflecting more extensive epileptogenic areas. Epilepsy surgery was performed to resect the right temporal lobe and portions of the frontal lobe. Pathology confirmed the presence of glial hyperplasia and abnormal neural migration. After 14 months, only occasional minor focal seizures were observed. DISCUSSION: Temporal MOGHE lesions have previously been reported; however, in those cases, ictal patterns were limited to the lesion because of early diagnosis. In our case, delayed diagnosis resulted in the development of epileptogenic areas. CONCLUSION: In patients with delayed diagnosis, brain areas with a high epileptogenic index may be discordant with the locations of MRI hallmarks of MOGHE. It is hypothesized that a larger resection may help decrease seizure frequency. However, additional large-sample studies are needed to confirm this.