In a review of 48 children who underwent temporal lobectomy for temporal lobe epilepsy, 16 patients had mass lesions in the temporal lobe. These mass lesions consisted of 12 tumors, 3 vascular malformations, and 1 arachnoid cyst. In 9 of 10 patients where the hippocampus was present in the pathological specimen and was not involved by tumor, there was concomitant mesial temporal sclerosis. All 16 patients have been followed for more than 1 year. Nine are free of seizures, with 4 of these 9 still on medication. Seven patients have had a greater than 50% reduction in seizures.