[Morphological findings in temporal lobe epilepsy: experience with 216 consecutive surgical specimens]

We have examined 216 consecutive surgical specimens of patients with chronic pharmacoresistant temporal lobe epilepsy. Neoplasms were detected in 75 cases (34.7%). All but two of these tumors were of low histopathological grade (WHO-grade I or II). There were 34 gangliogliomas, 17 pilocytic astrocytomas, 9 oligodendrogliomas, 6 fibrillary astrocytomas, and 6 dysembryoplastic neuroepithelial tumors. Fifty-one specimens contained non-neoplastic focal lesions and an additional 13 cases had both tumors and non-neoplastic focal lesions within the same specimen. The most frequent non-neoplastic focal lesions were microscopic glioneuronal hamartias (32 cases), glioneuronal hamartomas (7 cases) and vascular malformations (13 cases). The hippocampal formation was structurally well preserved in 71 specimens and in 51 of these (71.8%) there was Ammon's horn sclerosis. The findings document that intractable temporal lobe epilepsy is associated with significant structural alterations in the great majority of patients.