Tumors Arising in the Setting of Pediatric Chronic Epilepsy
RA Prayson, J Fong, I Najm. Cleveland Clinic Foundation, Cleveland, OH
Background: Along with malformations of cortical development (MCD), hippocampal sclerosis, and remote ischemic damage, tumors are among the more common identifiable causes of medically intractable seizures in pediatric age patients. This study reviews one institution's 20 year experience with tumors arising in this clinical setting.
Design: Retrospective review of 129 pediatric patients (less than 18 years of age, 65 females (54%)) with tumors and medically intractable seizures encountered during a 20 year period of time (1989 - 2009). Using the most recent WHO classification of brain tumors, tumor type and grade were assessed.
Results: The most common sites of origin included temporal lobe (N=77, 59.7%), parietal lobe (N=20, 15.5%), and frontal lobe (N=15, 11.6%). WHO grade included 73 (56.6%) grade I tumors, 32 (24.8%) grade II tumors, and 18 (14%) grade I/II tumors. In 6 cases (4.7%), a WHO grade is not associated with mass. Tumor types included : ganglioglioma (N=48, 37.2%), dysembryoplastic neuroepithelial tumor (N=17, 13.2%), low grade astrocytoma (N=15, 11.6%), low grade mixed glioma (N=8, 6.2%), low grade oligodendroglioma (N=5, 3.9%), meningioangiomatosis (N=4, 3.1%), angiocentric glioma (N=3, 2.3%), and dysembryoplastic neuroepithelial tumor/ganglioglioma composite tumor (N=3, 2.3%). Less frequently observed lesions (N=1 or 2) included pilocytic astrocytoma, protoplasmic astrocytoma, pleomorphic xanthoastrocytoma, and glioneuronal hamartoma. In 18 cases, distinction between low grade glioma and low grade glioneuronal tumor could not be definitively made. Coexisting MCD was noted in 19.4% of cases. In 4 tumors, coexistent hippocampal sclerosis was identified. Ki-67 labeling indices were less than 5% in all (N=51) cases assessed. Of 25 tumors evaluated for chromosome 1p status, only one low grade mixed glioma demonstrated evidence of deletion; only 1/22 evaluated tumors (a low grade mixed glioma) showed evidence of chromosome 19q deletion.
Conclusions: Collectively, WHO grade I glioneuronal tumors account for slightly more than half of all neoplasms which cause intractable epilepsy in pediatric patients. A significant minority of tumors (N=18, 14%) were difficult to definitively classify as glioma versus glioneuronal tumor, due on extent of sampling. Coexistent pathologies including MCD and hippocampal sclerosis may be observed in a significant minority of tumors, suggesting a possible developmental origin to some tumors arising in this setting.
Tuesday, March 23, 2010 1:00 PM
Poster Session IV # 243, Tuesday Afternoon