[Dysembryoplastic neuroepithelial tumor (DNT). Pattern of neuroradiologic findings]

Dysembryoplastic neuroepithelial tumors (DNT) were first described as a new tumor entity by Daumas-Duport et al. in 1988 and were introduced into the revised WHO classification of brain tumors in 1993. The purpose of this study was to work out neuroradiological CT and MRT patterns of DNT. Five patients, aged 11-61 years (three female, two male) underwent complete presurgical neuroradiological exploration (5 CT, 4 MRT investigations, 2 angiography) because of brain tumor. Four cases complained of seizures and one of occipital-located headache. Total microsurgical excision was achieved in two cases. Two further lesions were resected subtotally after stereotactic biopsy diagnosis. In one case, stereotactic biopsy alone was carried out. All DNTs were localized cortically: two frontobasal medial in the gyrus rectus, two temporobasal in the gyrus occipitotemporalis lateralis and one infratentorial in the lobus caudalis cerebelli. They were sharply demarcated from the surrounding brain tissue. Cortical localization was better visualized by MRT, especially on coronal and sagittal images. CT scans showed a hypodense lesion, MRT a high-signal intensity in T2, low signal in T1 and in proton-weighted images a hyperintense rim with a slightly hyperintense small cyst. The multinodular tumor architecture was best seen in MRT. Two DNTs presented partial contrast enhancement, while three DNTs did not take up contrast. In two lesions there were focal calcifications. The infratentorial DNT was associated with a bony defect of the tabula interna into which the tumor expanded. Two angiographies showed no pathological tumor neovascularization. A hypodense sharply demarcated lesion with a multinodular pattern in MRT with cortical location and without space-occupying signs is, in combination with the clinical symptom of epileptic seizures, highly suggestive of DNT. As our results demonstrate, DNT can also occur in the infratentorial space.