Sîrbu Journal of Medical Case Reports 2011, 5:441 http://www.jmedicalcasereports.com/content/5/1/441 Page 3 of 5 Figure 2 EEG showing interictal spikes and polyspikes. One minute of hyperventilation activated a tonic-clonic generalized seizure. DNT has a multinodular architecture, mainly in the cortex, and consists of oligodendrocytes, astrocytes, neu- rons, and glyconeural elements. This cortical structural abnormality disrupts normal neuronal circuitry and becomes an epileptogenic focus. Neuronal cells in the lesion may also secrete neurotransmitters or express receptors. Neuronal markers (synaptophysin, neuron- specific enolase) and glial markers (GFAP, S-100) are positive. Despite benign behavior, it may have a high MIB-1 labeling index. Aberrant expression of apoptosis- associated proteins (bcl-2, bcl-x, bax), similar to what has been previously described in gangliogliomas (another epilepsy-related, dysplasia-associated tumor), may play a role in the pathogenesis of DNT [2]. Today, DNT refers to polymorphic tumors that appear during embryogenesis. In the revised World Health Organiza- tion classification, DNTs have been incorporated into the category of neuronal and mixed neuronoglial tumors [3]. Non contrast-enhanced CT scans show well-demar- cated lesions that are hypodense relative to the sur- rounding brain, sometimes with intratumoral calcification and multicystic appearance. Routine MRI sequences reveal a well-demarcated lesion, hypointense on T1-weighted images, and hyperintense on T2- weighted images. Edema and mass effect on midline structures are lacking, although they may be observed in cases of hemorrhagic complications [4]. The lobular aspect with presence of septations can sometimes occur (as in our case). Single-photon emission CT has been used in limited fashion with DNTs, and this shows hypoperfusion or poor isotope uptake. MR spectroscopy allows the determination of certain biochemical proper- ties of the brain in vivo and reflects the biologic charac- teristics of benign tumor. The combination of preoperative positron emission tomographic metabolic studies with functional brain mapping allows for predic- tion of tumor type, defines eloquent areas of cortical function, and improves approach and resection of the tumors with minimal risk of neurological impairment. Differential diagnosis includes oligodendrogliomas, mixed gliomas and gangliogliomas. Treatment options and prognosis differ significantly between these lesions. It is important that DNT and glioma be correctly differ- entiated at diagnosis, because patients with DNT should not be subjected to potentially harmful adjuvant thera- pies such as radiation or chemotherapy. Our diagnosis was based on the characteristic imaging investigations, the stationary dimensions of the tumor during a follow-up of 13 years and the clinical expres- sion of epilepsy unresponsive to treatment. It is true