Abstracts

Rationale: Rationale: In the present study we characterized neocortical malformations in cases of refractory temporal lobe epilepsy and cortical dysplasia (CD) Methods: We studied 60 cases (40 males and 20 females), mean age 34.6 years, of refractory temporal lobe epilepsy and CD, only 8 with preoperative MR imaging suggestive of CD. All patients were studied according to standardized presurgical protocol and submitted to temporal lobectomy and amigalohippocampectomy. The expression and distribution of GFAP, nestin and vimentin, was studied immunocitochemically in T1, T2, and T3 regions. Results: We found marked dislamination in all areas of the cortex, neuronal loss, amylaceous bodies, neuronal cytomegaly with cytoskeletal disorganization containing dense fibrillar cytoplasmic aggregates, dysplastic neurons, balloon cells with atypical nuclei, often with binucleation, and abundant glassy eosinophilic cytoplasm. CD was classified as Type IA in 8.3%, Type IIA in 50%, and Type IIB in 15% of cases. Combined Type IA and IIA were found in 5%, Type IIA and IIB in 16.6% and Type IA and IIB in 1.6% of cases. GFAP, nestin and vimentin were highly expressed in the majority of neurons in the cortical areas as well as the hippocampus.The majority of balloon cells were found in the white substance. Expression of nestin was increased only in balloon cells and dysplastic neurons. Conclusions: These findings suggest that malformations of cortical development, up regulation of the astrocytic response as an astroglial dysfunction, and possible alterations in the blood brain barrier contribuite to high epileptogenic activity in these patients.