DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMORS - MR AND CT EVALUATION

PURPOSE: To evaluate dysembryoplastic neuroepithelial tumors (DNTs) on MR and CT studies and to compare DNT with other frequently encountere d epileptogenic glioneuronal lesions. METHODS: We analyzed the MR imag es and CT scans of 16 patients who had complex partial epilepsy and DN T with respect to tumor location, size, CT density, MR signal intensit y, mass effect, contrast enhancement, and heterogeneity, and compared these features with CT and MR findings in 51 cases of ganglioglioma an d 33 cases of glioneuronal malformation. RESULTS: DNTs were located in the temporal lobe in 14 patients and in the frontal lobe in 2 patient s. The cortex was involved in all cases and the subcortical white matt er in 10 cases, Fifty percent of the tumors had poorly defined contour s. On MR images, 14 DNTs had multiple cysts and 2 had single cysts. Co ntrast enhancement was observed in 6 DNTs, and mass effect was present in 9. CT scans disclosed moderately hypodense lesions in 7 patients a nd markedly hypodense cystic lesions in 6 patients. Two DNTs were calc ified. Tumor hemorrhage with perifocal edema was observed in 1 case. C ontrary to previous reports, slow but definite tumor growth was presen t during a 13-year period in 2 of 6 patients in whom serial CT or MR s tudies were obtained. CONCLUSION: A multicystic appearance on MR image s is a characteristic feature of DNT and corresponds to its myxoid mat rix and multinodular architecture. This feature is rare in ganglioglio mas and glioneuronal malformations, and, as such, may help differentia te DNTs from these disorders.