Dysembryoplastic neuroepithelial tumor.

Dysembryoplastic neuroepithelial tumor is a recently described but rare tumor that occurs in children and characterized by long-standing, intractable partial complex seizures. Due to a paucity of literature on this condition and its heterogeneous cellular composition, dysembryoplastic neuroepithelial tumors can present difficulties in diagnosis. The authors describe two cases of dysembryoplastic neuroepithelial tumor occurring in young patients (ages 8 and 19 years). Both tumors were located in the temporal lobe. Temporal lobectomy with excision of mesial structures resulted in resolution of the seizures. Differential diagnosis includes oligodendrogliomas, mixed gliomas, and gangliogliomas. Features of the dysembryoplastic neuroepithelial tumor that are useful in making the distinction include a multinodular and multicystic appearance, the presence of both neuronal and glial (oligodendrocytic and astrocytic) components with little if any cytologic atypia, the presence of accompanying cortical dysplasia, and the lack of an arcuate vascular pattern. Because dysembryoplastic neuroepithelial tumors are curable by excision, the recognition and correct diagnosis of this tumor is important.