[Neuropathologic data in drug-resistant partial epilepsy. Report of a series of 195 cases]

This report concerns the histopathological findings in 195 consecutive surgical specimens of patients with chronic drug-resistant epilepsy. Six pathological groups were identified corresponding to 63 tumors, 51 developmental lesions, 39 Ammon's horn sclerosis, 27 non specific changes, 11 glial or gliomesodermal scars and 4 Rasmussen's encephalitis. In 14 patients, 2 distinct abnormalities were observed with Ammon's horn sclerosis as one part of the dual pathology. All tumors were of low histopathological grade and included 30 dysembryoplastic neuroepithelial tumors, 17 gangliogliomas, 5 subependymal giant cell astrocytomas of tuberous sclerosis, 4 pleomorphic xanthoastrocytomas, 3 astroblastomas, 3 astrocytomas and 1 oligodendroglioma. Developmental lesions included 22 hamartomas, 12 focal dysplasias, 5 microdysgenesis, 1 nodular cortical heterotopia, 1 arachnoid cyst and 10 cavernomas. These findings emphasize two pathological features. Firstly, well-defined changes were present in all specimens. Secondly, the most common lesions were respectively tumors and developmental abnormalities.