We present a case of invasive monitoring of a patient while he was being surgically treated in the status state. Our patient was a 27-year-old male who was hospitalized for frequent seizures, which began after a head trauma at the age of 3. Video electroencephalography was performed, and 25 clinical seizures were observed in 24 h. Cranial magnetic resonance imaging revealed a T2 hyperintense and T1 hypointense lesion at the right frontal lobe and subependymal nodule. For the purpose of invasive monitoring, subdural electrodes were placed on the cortex surface via a right frontal craniotomy. The patient was reoperated, and epileptic zone resection was performed. There was no sign of neurological deficit. Histopathological examination revealed cortical tuber, and the patient was scanned for tuberous sclerosis. There was no sign of tuberous sclerosis in other organs. Our patient was diagnosed with tuberous sclerosis, cortical tuber, subependymal nodule, epilepsy, and intermediate mental retardation. Radiological diagnosis should also be considered. Cortical tuber can be confused with focal cortical dysplasia. Finally, staged resection may be necessary for surgical treatment in some cases.