Figure 3-12.

Images illustrating dysembryoplastic neuroepithelial tumors. A, B, T1 postgadolinium and T2-weighted images showing a dysembryoplastic neuroepithelial tumor associated with focal cortical dysplasia (confirmed in the postoperative histopathology) in the right temporal lobe in a 23-year-old man with refractory focal seizures since the age of 9. The patient became seizure free after lesionectomy. C, D, Coronal T1 and axial T2-weighted images showing a dysembryoplastic neuroepithelial tumor in the right temporal lobe of a 26-year-old woman experiencing seizures since childhood. She became seizure free after lesionectomy. Dysembryoplastic neuroepithelial tumors are hypodense in CT scan and may show calcifications. Close to one-third of the cases show contrast enhancement. In MRI the lesion is often limited to the cortex and is hypointense on T1 (A, C) and hyperintense on T2 sequences (B, D). There is no peritumoral edema or mass effect; variable contrast enhancement may be present (A, arrow).