title: A case of secondary somatosensory epilepsy with a left deep parietal opercular lesion: successful tumor resection using a transsubcentral gyral approach during awake surgery.
abstract: Few studies have examined the clinical characteristics of patients with lesions in the deep parietal operculum facing the sylvian fissure, the region recognized as the secondary somatosensory area (SII). Moreover, surgical approaches in this region are challenging. In this paper the authors report on a patient presenting with SII epilepsy with a tumor in the left deep parietal operculum. The patient was a 24-year-old man who suffered daily partial seizures with extremely uncomfortable dysesthesia and/or occasional pain on his right side. MRI revealed a tumor in the medial aspect of the anterior transverse parietal gyrus, surrounding the posterior insular point. Long-term video electroencephalography monitoring with scalp electrodes failed to show relevant changes to seizures. Resection with cortical and subcortical mapping under awake conditions was performed. A negative response to stimulation was observed at the subcentral gyrus during language and somatosensory tasks; thus, the transcortical approach (specifically, a transsubcentral gyral approach) was used through this region. Subcortical stimulation at the medial aspect of the anterior parietal gyrus and the posterior insula around the posterior insular point elicited strong dysesthesia and pain in his right side, similar to manifestation of his seizure. The tumor was completely removed and pathologically diagnosed as pleomorphic xanthoastrocytoma. His epilepsy disappeared without neurological deterioration postoperatively. In this case study, 3 points are clinically significant. First, the clinical manifestation of this case was quite rare, although still representative of SII epilepsy. Second, the location of the lesion made surgical removal challenging, and the transsubcentral gyral approach was useful when intraoperative mapping was performed during awake surgery. Third, intraoperative mapping demonstrated that the patient experienced pain with electrical stimulation around the posterior insular point. Thus, this report demonstrated the safe and effective use of the transsubcentral gyral approach during awake surgery to resect deep parietal opercular lesions, clarified electrophysiological characteristics in the SII area, and achieved successful tumor resection with good control of epilepsy.
authors: Department of Neurosurgery, Nagoya University Graduate School of Medicine;|Brain and Mind Research Center, Nagoya University;
authors: Satoshi
authors: S
authors: Maesawa
authors: Department of Neurosurgery, Nagoya University Graduate School of Medicine;
authors: Masazumi
authors: M
authors: Fujii
authors: Department of Rehabilitation, National Hospital Organization, Nagoya Medical Center; and.
authors: Miyako
authors: M
authors: Futamura
authors: Information and Communications Headquarters, Nagoya University, Nagoya, Japan.
authors: Yuichiro
authors: Y
authors: Hayashi
authors: Department of Neurosurgery, Nagoya University Graduate School of Medicine;
authors: Kentaro
authors: K
authors: Iijima
authors: Department of Neurosurgery, Nagoya University Graduate School of Medicine;
authors: Toshihiko
authors: T
authors: Wakabayashi
mesh_terms: D001254:Astrocytoma / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000150:complications / Q000175:diagnosis / Q000601:surgery*; D004827:Epilepsy / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D006801:Humans; D008297:Male; D013003:Somatosensory Cortex; D055815:Young Adult
keywords: EEG = electroencephalography; SII = secondary somatosensory cortex; SLTA = Standard Language Test of Aphasia; WAIS-III = Wechsler Adult Intelligence Scale-III; WMS-R = Wechsler Memory Scale-R; awake surgery; diagnostic and operative techniques; parietal operculum; secondary somatosensory epilepsy; subcentral gyrus