Computed tomography in chronic seizure disorder caused by glioma.

Since the introduction of computed tomography (CT) in 1974, 137 patients underwent cortical resection for intractable epilepsy. The CT scans of 32 of these patients demonstrated an isolated calcified or hypodense lesion of unknown origin. The mean interval from onset of the seizure disorder to surgery was 11 years. The referring physicians frequently considered these lesions to be of nonneoplastic origin, which usually delayed surgical management. Twenty-six of the 32 patients, however, proved to have a cerebral glioma, seven showing anaplastic changes. Because the majority of these patients were found to have a neoplasm and especially because the CT scan could not distinguish between a well-differentiated glioma and those with anaplastic changes, we recommend early surgical treatment in patients with chronic seizure disorders who are found to have an isolated lesion of unknown origin on CT scan.