Surgical neuropathology of intractable epilepsy

Pathological examination of surgical specimens from patients with intractable epilepsy has been performed more frequently as neurosurgical procedures have been increasingly applied to the control of pharmacoresistant intractable epilepsy. The pathological lesions are classified as (a) hippocampal sclerosis of various degree with or without extrahippocampal dual pathology, (b) glioneuronal malformative lesions (including focal cortical dysplasia, hemimegalencephaly, tuberous sclerosis, microdysgenesis) with or without coexistence of tumor or tumor-like lesions, (c) vascular lesions [including arteriovenous malformations (AVM) and hemangioma], (d) tumors alone, (e) chronic inflammatory or infectious lesions, (f) ulegyric lesions (including traumatic, ischemic, or undetermined episodes) with or without siderotic changes, (g) gliosis or astrocytic proliferation alone, (h) concomitant calcified lesions, and (i) unspecified lesions. We discuss recent factors with regard to this classification.