Mixed glioneuronal tumor: a dysembryoplastic neuroepithelial tumor with rosette-forming glioneuronal tumor component.

Neuronal and mixed neuronal-glial tumors of the CNS show a wide spectrum of components. Here, we report an unusual case of brain tumor with combined histological features of dysembryoplastic neuroepithelial tumor (DNT) and rosette-forming glioneuronal tumor (RGNT) in a 23-year-old man. It arose in the left anterior cingulate cortex with a pseudo-polycystic appearance on neuroimaging. Histological features contained the "specific glioneuronal element" mimicking DNT and the components of distinct neurocytic rosettes with a center of neuropil islands and pilocytic astrocytoma resembling RGNT. Although the mechanisms of mixed glioneuronal tumor are far from being well-known, their co-existence might suggest a possible etiologic relationship between DNT and RGNT.