Brain tumors are a common cause of epilepsy in adults. More than one-third of the 35,000 patients per year with newly diagnosed brain tumors develop epileptic seizures. If the tumor involves the cerebral hemispheres, seizures occur in at least 50% of cases.17,18

Some predictive factors for seizure occurrence include:81,83

• tumor location in the frontal or parietal regions
• evidence of cerebral hemispheric dysfunction
• incomplete tumor resection

Any brain tumor, benign or malignant, common or uncommon, can cause seizures.19–23 Those more highly associated with the development of epilepsy include:83,88

• melanoma
• hemorrhagic lesions
• multiple metastases
• slowly growing primary tumors
• tumors near the Rolandic fissure

Patients with low-grade tumors may be more likely to develop epilepsy, possibly because their longer survival allows more time for seizures to develop.81 One retrospective study found a median interval of 8 weeks between diagnosis of a brain tumor and a first seizure.83

The tumors most often presenting with seizures in adults are:24–30

• dysembryoplastic neuroepithelial tumors (DNETs) 90-100
• ganglioglioma59
• glioblastoma multiforme34
• low-grade astrocytoma69
• meningioma27
• metastatic tumors41
• oligodendroglioma70-90

Epilepsy in children is associated with brain tumors less often than in adults. Tumors still must be ruled out, however, even if the child has no neurologic deficits.32–34 If a tumor is diagnosed, up to 46% of these patients may have intractable seizures.32,35,36 Most tumors occur in the temporal or frontal lobes. As in adults, epileptogenic brain tumors in children may be benign or malignant. The most common tumors associated with epilepsy in children are:30,36–38

• gangliogliomas
• low-grade astrocytomas
• DNETs
• oligodendrogliomas

Adapted from: Mangano FT, McBride AE, and Schneider SJ. Brain tumors and epilepsy. In: Ettinger AB and Devinsky O, eds. Managing epilepsy and co-existing disorders. Boston: Butterworth-Heinemann; 2002;175–194.
With permission from Elsevier (www.elsevier.com).
Reviewed and revised March 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.