PRE-SURGERY MR-VISUALIZATION OF THE EPILEPTOGENIC SUPRATENTORIAL BRAIN TUMORS IN CHILDREN

Abstract

Symptomatic focal epilepsies are commonly caused by the supratentorial brain tumors in chtldren. Among the 79 pediatric patients with supratentorial brain tumors 56 patients had symptomatic epilepsy (69,3%). The most epileptogenic tumors were dysembryoplastic neuroepithelial tumors (DNET), diffuse astrocytomas (DA) and gangliogliomas (GG). In all the cases of DNET and in 4 patients with GG epileptic seizures were the first manifestation, and in 4 of 5 cases of DNEO they were the only clinical sign of tumor. On the neuroimaging the MR-features of DNET, DA and GG were represented by iso- or hypointensive signal on T1 weighted image (WI) and varying in intensity from moderate to hyperintensive signal in T2 and FLAIR WI, while in cases with DNET and GG practically no mass effect and perifocal edema were seen, and on FLAIR WI the so-called "spume-like" (multicystic) structure was most clearly observed. During the follow up period no significant changes in the dimensions of identified DNET and GG were observed. In one case the combination of DNET with focal cortical dysplasia was noted. In DA it is difficult to distinguish the perifocal edema from tumorous tissue and normal brain tissue, and the growth potential of tumor is slow. The contrast enhancement of these tumors is ambiguous. Along with DNET (which is epileptogenic in 100% of cases), the most epileptogenic brain tumors are DA (in 91.7% of cases) and GG (in 80% of cases) which should be excluded in drug-resistant cases of focal epilepsy.