Abstracts

Rationale: Although the hippocampus is considered as an important site of seizures in mesial temporal lobe epilepsy (mTLE), the amygdala may also play a significant role in the epileptogenesis of mTLE. Amygdala enlargement is often found in patients with mTLE, and volumetric detection of amygdala enlargement has been documented in image-negative TLE patients. However, only limited data have been reported on the clinical features, surgical outcomes, and pathological characteristics in mTLE patients with amygdala enlargement. Methods: We recruited epilepsy patients who had undergone surgical treatment for refractory epilepsy with radiological evidence of amygdala enlargement. All patients showed homogenously increased amygdala volumes on MRI without enhancement and underwent surgical treatment for mTLE. Results: A total of 12 patients were included, and 11 became seizure free. Pathology results revealed that eight patients had focal cortical dysplasia (FCD), two had ganglioglioma, one had oligodendroglioma, and one had astrocytoma. The clinical features, MRI findings and clinical features were largely indistinguishable between the patients with brain tumors and those with FCD, but the patients with brain tumors tended to be younger at the time of seizure onset. Conclusions: Our study showed that surgical treatment of epilepsy in patients with amygdala enlargement usually has a favorable outcome. FCD was the most frequent pathological diagnosis in these patients. However, a brain tumor should be considered in the differential diagnosis, especially in young patients, because it is often difficult to differentiate FCD from a brain tumor in radiological findings.