The results of operation for treatment of epilepsy in 5 male and 4 female patients with tuberous sclerosis (TSC) in a 5-year period from 1986-1990 are reported from the Mayo Clinic. Pathological examination of resected lesions demonstrated 7 cortical tubers and 2 astocytic hamartomas. MRIs correlated with clinical and focal EEG findings. Seven patients are free from seizures and 2 are partially controlled. In selected TSC patients with single or multiple cerebral lesions, both the primary and secondary epileptogenic lesions were modified by removal of the primary ictal focus. 
COMMENT. Results of surgery for epilepsy due to cortical dysplasia (CD) are reviewed in 17 patients treated at the Maudsley Hospital, London . Only 6 became free or almost free from seizures, and 8 had no relief. Outcome related to the extent of the pathology but not to histology. Lesions outside the temporal and frontal lobes and generalized interictal EEG abnormalities, reflecting extensive or multiple lesions, correlated with poor surgical outcome. MRI was abnormal in 5 of 7 patients examined, contrasting with a low detection rate of abnormalities by CT scan. The use of MRI and PET should improve the identification of CD patients amenable to surgery.