%0 Journal Article
%T Focal Epilepsy Associated with Glioneuronal Tumors
%A Giulia Loiacono
%A Chiara Cirillo
%A Francesco Chiarelli
%A Alberto Verrotti
%J ISRN Neurology
%D 2011
%R 10.5402/2011/867503
%X Glioneuronal tumors are an increasingly recognized cause of partial seizures that occur primarily in children and young adults. Focal epilepsy associated with glioneuronal tumors is often resistant to pharmacological treatment. The cellular mechanisms underlying the epileptogenicity of glioneuronal tumors remain largely unknown. The involved mechanisms are certain to be multifactorial and depend on specific tumor histology, integrity of the blood-brain barrier, characteristics of the peritumoral environment, circuit abnormalities, or cellular and molecular defects. Glioneuronal tumors presenting with epilepsy were observed to have relatively benign biological behavior. The completeness of the tumor resection is of paramount importance in avoiding tumor progression and malignant transformation, which are rare in cases of epileptogenic glioneuronal tumors. An evolving understanding of the various mechanisms of tumor-related epileptogenicity may also lead to a more defined surgical objective and effective therapeutic strategies, including antiepileptogenic treatments, to prevent epilepsy in at-risk patients. 1. Introduction Glioneuronal tumors are an increasingly recognized cause of partial seizures that occur primarily in children and young adults [1, 2]. These are tumors with an admixture of glial and neuronal components. Both cell types are thought to be part of the same neoplastic process. Entrapment of preexisting neurons by an infiltrating glioma therefore has to be distinguished from glioneuronal tumors. More well-established examples of glioneuronal tumors include dysembryoplastic neuroepithelial tumors (DNTs) ganglioglioma and desmoplastic infantile ganglioglioma. More recently recognized entities partly included in the latest version of the WHO classification include the rosette-forming tumor of the fourth ventricle the papillary glioneuronal tumor and rosetted glioneuronal tumor/glioneuronal tumor with neuropil-like islands. The glial component in these tumors varies but often resembles either a pilocytic astrocytoma or an infiltrating glioma with astrocytic or oligodendroglial features [3]. Gangliogliomas and DNTs arise most commonly in the temporal lobe and appear to be associated with an increased incidence of cortical dysplasia or neuronal migration abnormalities [1, 4, 5]. Focal epilepsy that is often resistant to pharmacological treatment is a common presenting symptom of glioneuronal tumors [1, 2]. Even though the biological behavior of these tumors is usually benign, especially when patients present only with epilepsy, cases of tumor
%U http://www.hindawi.com/journals/isrn.neurology/2011/867503/