Pathophysiology of Brain Tumor-Related Epilepsy

Epilepsy is common in patients with brain tumors, frequently even as presenting symptom, and can affect quality of life. The pathogenesis of tumor-related epilepsy is poorly understood. Several factors including tumor type, tumor location, and peritumoral and genetic changes are probably involved. Tumor cells themselves may present intrinsic epileptogenicity and inadequate homeostasis in the peritumoral tissues may lead to seizure susceptibility. Changes in amino acid neurotransmission, hypoxia, acidosis, metabolic, immunological, and inflammatory changes are considered as important mechanisms underlying tumor-related seizures. Moreover, seizures are often refractory to antiepileptic treatment; drug interactions and overexpression of multidrug resistance-related proteins in tumors that restrict the penetration of antiepileptic drugs into the brain may partially explain multidrug resistance. A more detailed knowledge of the pathophysiologic mechanism involved in tumor-related seizures is necessary to provide new strategies for surgical and medical treatment of this condition.