Continuous ictal discharges with high frequency oscillations confined to the non-sclerotic hippocampus in an epileptic patient with radiation-induced cavernoma in the lateral temporal lobe

Abstract Background Intraoperative electrocorticography(iECoG) recording is recommended for treating cavernoma related epilepsy. However, "interictal" paroxysmal activities are generally recordable but are not always identical to the epileptogenic zone. Case Description We surgically treated a 15-year-old girl with drug-resistant epilepsy associated with radiation-induced cavernoma in the right lateral temporal lobe. iECoG revealed paroxysmal activities in the cortex around the cavernoma. Additionally, continuous subclinical " ictal" discharges with high-frequency oscillations (HFO), confined to the histologically non-sclerotic hippocampus, were recorded. Following additional hippocampectomy, a good seizure outcome was obtained. Conclusion iECoG and HFO analysis revealed high epileptogenicity in the non-sclerotic hippocampus of this patient.