ILAE focal cortical dysplasia type IIIc in the ictal onset zone in epileptic patients with solitary meningioangiomatosis

"Solitary" meningioangiomatosis (MA) is a rare, benign, hamartomatous lesion of the cerebral cortex and frequently leads to epilepsy. However, the source of the epileptogenicity in meningioangiomatosis remains controversial. We report two surgically-treated meningioangiomatosis cases with medically intractable epilepsy. In both cases, chronic subdural electrocorticogram (ECoG) recordings identified the ictal onset zone on apparently normal cortex, adjacent to and/or above the meningioangiomatosis lesion, not on the meningioangiomatosis lesion itself. The ictal onset zone was resected, along with the MA lesion, and good seizure outcome was achieved. Histological examination of the ictal onset zone revealed the presence of ILAE focal cortical dysplasia (FCD) type IIIc. Our case studies suggest that in the surgical management of epilepsy with meningioangiomatosis, it is important to identify undetected, but epileptogenic, ILAE FCD Type IIIc, using preoperative multimodal examinations, including chronic ECoG recordings.