NEUROPATHOLOGICAL FINDINGS IN RESECTIVE S URGERY FOR MEDICALLY-INTRACTABLE EPILEPSY - A STUDY OF 195 CASES

This report concerns the histopathological findings in 195 consecutive surgical specimens of patients with chronic pharmacoresistant epileps y. 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 encephalit is. In 14 patients, 2 distinct abnormalitites were observed with Ammon 's horn sclerosis as on part of the dual pathology. All tumors were of low histopathological grade and included 30 dysembryoplastic neuroepi thelial tumors, 17 gangliogliomas, 5 subependymal giant cell astrocyto mas of tuberous sclerosis, 4 pleomorphic xanthoastrocytomas, 3 astrobl astomas, 3 astrocytomas and 1 oligodendroglioma. Developmental lesions included 22 hamartomas, 12 focal dysplasias, 5 microdysgenesis, 1 mod ular cortical heterotopia, 1 arachnoid cyst and .10 cavernomas. These findings emphasize two pathological features. Firstly. well-defined ch anges were present in all specimens. Secondly, the most common lesions were respectively tumors and developmental abnormalities.