Dysembrioplastic neuroepithelial tumor: cytological diagnosis by intraoperative smear preparation.

The dysembrioplastic neuroepithelial tumor (DNT) is a benign and slow-growing temporal lobe cortical lesion that presents with clinically unresponsive partial and complex seizures, with onset before age 20 yr. DNT shows a multinodular architecture and the presence of mixed glioneural elements. The authors report on a case of DNT diagnosed by the intraoperative smear cytological technique. We describe the cytological characteristics of smear preparations of DNT, with emphasis on the differential diagnosis. The authors present a 5-yr-old male with partial seizures for the preceding 3 yr. The patient showed no other neurological deficits. Magnetic resonance identified a lesion in the cortical area of the right temporal lobe. The smear cytology showed small, round, oligodendroglial-like cells arranged in lobules, with microcystic spaces containing ganglion cells floating in a fine fibrillary background. Histology confirmed the diagnosis of DNT. This report shows that the smear preparation can be trustworthy for the intraoperative diagnosis of DNTs, helping to determine the appropriate neurosurgical procedure and thus avoiding extensive and unnecessary resections.