A Surgical Case of Intractable Epilepsy Originating from the Primary Sensory Area for the Hand
Authors: Asano Eishi , Otsuki Taisuke , Ito Kenji , Takahashi Hirotatsu , Soga Takashi , Ishikawa Shuichi , Nakasato Nobukazu , Yoshimoto Takashi 
Published: August 2009

Purpose: It has been considered difficult to resect the primary sensory areas, except for the areas of the face and tongue, without causing severe sensory deficits. We now report a surgical case of intractable epilepsy that originated from the hand area of the primary sensory cortex.

Case Report: A 14‐year‐old girl was first seen with daily sensory seizures of the left upper extremity with secondary generalization. She was born at full term with an uneventful delivery, and her developmental milestones were normal. She had a history of febrile convulsions from age 1–3 years. At age 6 years, she had generalized clonic seizures preceded by clonic seizures of the left upper extremity. She was diagnosed with symptomatic epilepsy with porencephaly in the right parietal lobe, as demonstrated by computed tomography (CT) scan, and medical treatment was commenced. At age 11 years, daily sensory partial seizures in the left hand were noted, and secondarily generalized seizures occurred several times a month. Her seizures started with numbness in the left band and progressed to clonic movement of the left wrist, a sensation of fear, and asymmetric tonic posturing with the left arm extended and the right arm flexed, eventually followed by secondarily generalized clonic seizure. The neurologic examination showed no sensory deficits, and the Wada test revealed a left language dominance. T1‐weighted magnetic resonance (MR) images demonstrated a low‐signal lesion of 1.5 × 2.0 × 3.0 cm at the right postcentral gyrus with a subcortical enhanced nodule, whereas T2‐weighted MR images revealed the lesion to be a homologous high‐signal lesion. Magnetoencephalography (MEG) demonstrated the lesion to be located at the postcentral gyrus between the localization of the dipole sources for the somatosensory evoked field obtained by both left median and ulnar nerve stimulation. The single‐photon‐emission CT (SPECT) showed an area of hypoperfusion surrounding the lesion, a part of which was demonstrated as hyporperfusion with the ictal SPECT. The scalp EEG showed no apparent paroxysms interictally, and there were no lateralized findings ictally. Intracranial EEG recording with subdural grids disclosed an ictal onset zone at the postcentral gyrus adjacent to the lesion, which was confirmed to be the primary sensory area for the hand by cortical stimulation. A meticulous lesionectomy and multiple subpial transections of the adjacent cortices were performed. Postoperatively, she complained of transient mild numbness in the left fingers for several days, but this has disappeared completely without any residual sensory deficits. Her seizures have disappeared completely for 2 years since the surgery. The surgical specimen was diagnosed as a dysembryoplastic neuroepithelial tumor (DNT). Postoperative neuropsychological evaluation showed significant improvement in memory scores on the Wechsler Memory Scale.

Conclusions: A surgical case of intractable epilepsy that originated from the primary sensory cortex for the hand was reported. After the resection of the DNT localized in the cortex, the patient was free of seizures and had no sensory deficits.