Epilepsy associated with low-grade brain glial neoplasms

In 1991-1993, 52 patients underwent surgery for low-grade supratentorial glioma. In 37 of them (astrocytoma 22, oligodentrocytoma 12, oligodendroglioma 2) seizures, often refractory to drug therapy, appeared as the first symptom. These cases were retrospectively analyzed. The patients had partial seizures: simple, complex, or secondarily generalized (preoperative duration: from 3 days to 17 years (mean 2 years); frequency: between 1 and 2/year and over 10/day). Neurological examination either revealed slight focal changes or was normal. Conventional craniotomy and resection of a tumor, without intraoperative electrocorticography, was performed. Partial resection was performed in 73%, subtotal in 5%, "total" in 22% of the cases. Postoperatively, 27 patients had focal radiotherapy, 3 of them in combination with chemotherapy. Two patients were reoperated. Out of 33 alive (89%), about two-thirds appear normal by neurological examination and are seizure-free at present (mean follow-up period 28 months). Most remain on antiepileptic drugs at lower doses. Histological and immunohistochemical analyses of resected tissue together suggest that the peripheral zone of cortical tumor infiltration may participate on epileptogenesis.