Pathological assessment of epilepsy surgery brain tissue

Surgical resection represents a successful strategy to achieve seizure control in patients with drug resistant epilepsy. In the last years increasing importance has been recognized to pathological substrate for epilepsy classifications and for predicting seizure and neuropsychological outcome after surgery. The current histopathological classifications of epilepsy-associated abnormalities certainly represent an amazing effort to overcome the limits of the previous classifications and constitute a formidable tool in the management of patients after epilepsy surgery. However the correct application of the recent ILAE classification systems begins with a proper epilepsy surgery technique, able to provide "en bloc" and "spatially oriented" surgical specimens and continues with the use of an appropriate pathological workup and reproducible stains. This methodological approach permits to relate the surgical outcome to the specific pathological findings, the site of the lesion, and the surgical strategy. These data are essential to an adequate preoperative patient and family counselling. Furthermore in this paper, besides the workup and the classification systems, we evidence some aspects which may be challenging and sometime misleading in clinical practice. In conclusion, a pathology based approach to epilepsy surgery is essential and might improve the interpretation of the outcomes and the comprehension of the causes of failures.