[Pathology of intractable epilepsy with regard to surgical treatment]

There have recently been a number of new pathological findings of specimens from epileptic foci that have increasingly been highlighted as opportunities for surgical treatment. These findings include a wide range from hippocampal sclerosis-related lesions of temporal lobe epilepsy to newly established malformative lesions. As to the former, special interest has been paid to additional knowledge regarding the pathology inside and outside the medial temporal regions, such as the significance of 1) accumulation of corpora amylacea in hippocampal sclerotic lesions, 2) dispersion of the granular layer of the dentate gyrus, 3) various pathologic features in the lateral temporal lobe, and 4) dual pathology in extratemporal areas. As increasing opportunities for surgical treatment of intractable epilepsy, new categories of malformative lesions are being established, including focal cortical dysplasia and microdysgenesis, the latter of which can be diagnosed only by pathological examination after surgery. In the field of surgical pathology of epilepsy patients, further clues to clarify the pathomechanism of epilepsy remain to be discovered.