[Epilepsy-associated tumors of the central nervous system: Epilepsy surgery and oncological aspects]

Among the tumors associated with chronic epilepsy, dysembryoplastic neuroepithelial tumor and ganglioglioma are the most common besides angiocentric glioma, pleomorphic xanthoastrocytoma and pilocytic astrocytoma. These tumors are usually considered as being benign.

To determine the best conservative and surgical treatment of tumors associated with epilepsy.

This article presents case reports of malignant transformation of a dysembryoplastic neuroepithelial tumor and of a tumor initially diagnosed as a ganglioglioma based on magnetic resonance imaging (MRI) criteria. Description of references in the literature on epilepsy surgery and the neuro-oncology of epilepsy-associated tumors.

In the case of the initially histopathologically diagnosed dysembryoplastic neuroepithelial tumor, a malignant transformation occurred 5 years after incomplete resection. The differentiation from a glioblastoma was possible through the analysis of the methylation profile. In another case a tumor assumed to be a ganglioglioma showed an increase in size after 6 years. Initial histopathological results revealed a glioblastoma. The analysis of the methylation profile suggested the diagnosis of an anaplastic pleomorphic xanthoastrocytoma and as a differential diagnosis an anaplastic ganglioglioma. Tumor progress correlated with the worsening of seizures.

Recent studies have shown that in the treatment of predominantly benign epilepsy-associated tumors neuro-oncological aspects should also be taken into account in addition to the epileptological considerations. In the case of malignant transformation epigenetic screening (methylation profiles) can help to classify the tumor entity more precisely.