Glioneuronal Tumors: Insights into a Rare Tumor Entity

Abstract

Glioneuronal tumors are a group of rare neoplasms made up of neural and glial components in heterogenous proportions, generally exhibiting WHO grade I clinical behavior. These tumors affect infants, children and young adults, but are also described in adults and the elderly. They are strongly associated with seizures. Tumor subtypes described under the umbrella of glioneuronal tumors are actively evolving but to date comprise central, extraventricular and lipo- neurocytoma, desmoplastic infantile astrocytoma and ganglioglioma, diffuse leptomeningeal glioneuronal tumor, dysembryoplastic neuroepithelial tumor, papillary glioneuronal tumor, rosette-forming glioneuronal tumor of the fourth ventricle, rosetted glioneuronal tumor with neuropil-like islands, gangliocytoma, ganglioglioma, anaplastic ganglioglioma and paraganglioma. They vary in radiographic appearance, with some exhibiting large heterogenous solid/cystic masses. With large scale genetic and molecular analyses ongoing, classification continues to evolve. Seizure management and surgical resection represent the cornerstones of management, with the use of systemic agents and radiation lacking conclusive results. Optimal management requires multidisciplinary discussion including neuro-oncological and neuro-surgical expertise due to both the rarity of these tumors and the lack of evidence with data confined to small retrospective series and reviews.