Diagnostic features of negative MRI epileptogenic focal cortical dysplasia

Objective To explore the diagnostic features of focal cortical dysplasia (FCD). Methods The patient was a young women, and was admitted to neurology department of the Affiliated Hospital of Jining Medical University for convulsion and unconsciousness. The clinical data of negative MRI epileptogenic FCD was analyzed retrospectively. Literatures were reviewed and features of clinical diagnosis of FCD were summarized. Results The patient had a history of epilepsy over 12 years with taking kinds of antiepileptic drugs (sodium valproate sustained release tablets, levetiracetam tablets, carbamazepine tablets), which were of poor curative effect. On admission, valproate plasma concentration was 0.05 μg/L. Electroencephalogram(EEG) showed that the right posteri head, especially the right parietal lobe was frequently scattered or clustered with a high amplitude spike, a slow compound wave. The MRI of epilepsy sequence was negative, while the 18F-FDG PET/CT showed a significant decrease in glucose metabolism in the right parietal lobe. And finally the FDG-PET/MR showed abnormal signal on the right parietal lobe. After the preoperative evaluation was complete, the epileptic foci resection of right parietal lobe was performed. The posterior arachnoid of the right parietal lobe was thickened and cerebral cortex atrophy was seen in the operation. The result of pathology proved to be FCD Ⅱa type. After 6 months follow-up, the patient did not have an epileptic seizure. Conclusions Diagnosis of MRI negative FCD has certain difficulties, it needs to be combined with clinical doctors′ experience, patients′ clinical manifestations, imaging examination, etc. FCD is an important cause of drug refractory epilepsy, and it should also be suspected that FCD occurs when the lesion is not detected by MRI. Key words: Epilepsy; Focal cortical dysplasia; Magnetic resonance imaging; Diagnosis