Brain tumors and epilepsy.

When treating patients harboring a brain tumor, it is mandatory to integrate the dogmas of epilepsy into a neuro-oncological viewpoint. The frequency of seizures differs widely between low- and high-grade tumors because of different mechanisms of epileptogenesis. The modern theories of pathological neural networks, especially in low-grade gliomas, can provide the key for an in-depth understanding of the principles of connectionism that underline both seizures, cognitive impairment and plasticity. It is a consuetude that principles of general management of patients with nontumor-related epilepsy are applied to neuro-oncology. Nevertheless, since tumors are complex evolving lesions requiring a multidisciplinary treatment approach (surgery, radiotherapy and chemotherapy), it is mandatory to have a comprehensive view of the natural history of each lesion when choosing the best antiepileptic drug. More than two thirds of patients with brain tumors and medically intractable epilepsy benefit from (sub)total surgical resection. Therefore, these patients are good surgical candidates both for oncological and epileptological considerations, in order to change the natural history of the lesion and to improve the quality of life at the same time. However, 15% of patients still have intractable medical seizures after surgery. Moreover, the insula may participate more often than usually considered in (intractable) seizures. Therefore, in these patients, invasive EEG recordings and eventually a second epilepsy surgery might be proposed.