Peritumoral edema and seizure in patients with cerebral convexity and parasagittal meningiomas.

Epileptogenic factors associated with cerebral convexity or parasagittal meningiomas were investigated by retrospective analysis of clinical symptoms and computed tomographic findings in 83 consecutive patients. The patients were divided into Group A consisting of 27 patients presenting with epilepsy as the first symptom, and Group B consisting of 56 patients presenting with other symptoms. Tumor location, tumor size, histological subtype, and the amount of peritumoral edema were compared between the groups. Tumor size, location, and histological subtype did not differ significantly between the two groups, but the area of peritumoral edema was significantly greater in Group A than in Group B. Similar results were found in subgroups of patients with frontal meningioma, central meningioma, and fibroblastic meningioma. Generalized seizures tended to occur in patients with frontal or fibroblastic meningioma, and partial seizures in those with central or parietal meningioma. Peritumoral edema is a significant epileptogenic factor associated with both cerebral convexity and parasagittal meningiomas, and may be especially related to the occurrence of secondarily generalized seizures in frontal and fibroblastic meningiomas.