Perifocal edema is a risk factor for preoperative seizures in patients with meningioma WHO grade 2 and 3.

Preoperative seizures were frequently encountered in about every third patient with meningioma WHO grade 2 or 3. Patients presenting with peritumoral edema on preoperative imaging are at particular risk for developing tumor-related seizures. Tumor resection was highly effective in achieving seizure freedom.