SURGICAL PATHOLOGY OF TEMPORAL-LOBE EPILEPSY - EXPERIENCE WITH 216 CASES

The surgical treatment of chronic epilepsies is increasing rapidly. He re we report the histopathologic findings in 216 consecutive surgical specimens of patients with chronic pharmacoresistant temporal lobe epi lepsy. In 75 cases (34.7%) there were tumors, all but two of which wer e of low histopathological grade (WHO grade I or II). The most common tumors were gangliogliomas (34 cases), pilocytic astrocytomas (17 case s), oligodendrogliomas (9 cases), fibrillary astrocytomas (6 cases), a nd dysembryoplastic neuroepithelial tumors (6 cases). There were 51 ca ses with non-neoplastic focal lesions and an additional 13 cases with tumors and non-neoplastic focal lesions within the same specimen. The most frequent non-neoplastic focal lesions were microscopic glioneuron al hamartias (32 cases), glioneuronal hamartomas (7 cases), and vascul ar malformations (13 cases). The hippocampal formation was structurall y well preserved in 71 specimens. In 51 of these (71.8%) there was Amm on's horn sclerosis. Presurgical placement of depth electrodes was inv ariably associated with circumscribed defects of the brain parenchyma. The implantation of subdural electrodes was sometimes followed by chr onic inflammatory changes of the leptomeninges. Our findings indicate that in the majority of patients with medically intractable temporal l obe epilepsy there are significant histopathologic findings, many of w hich are only rarely encountered otherwise.