Vascular abnormalities in surgical specimens obtained from the resected focus of intractable epilepsy.

The histopathological features, particularly hypervascularity, were examined in specimens resected from 21 patients, 15 with intractable epilepsy accompanying cortical dysplasia or dysembryoplastic neuroepithelial tumor (DNT), and 6 with benign brain tumors, such as ganglioglioma and low-grade glioma. Hypervascularity was found in resected specimens from 15 of the 21 patients (71.4%) and in 10 of the 12 patients (83.3%) who had double pathology. Counting of numbers of vessels by CD31 immunohistochemistry revealed that hypervascularity was prominent, especially in cases of vascular malformation or cortical dysplasia. However, almost all cases were negative for vascular endothelial growth factor (VEGF) staining, except for some cases of benign brain tumors. Moreover, all cases showed low or no proliferative potential in MIB-1 immunohistochemistry. These results suggest that the etiology of hypervascularity in the dysplastic lesions is one of a variety of cerebral malformations, as is the case with abnormal maturation and differentiation in neuroglial elements.