Dysembryoplastic neuroepithelial tumors (DNETs) are benign lesions found in young people with a history of partial, drug-resistant seizures without progressive neurologic deficit (either no neurologic deficit or stable deficit).
DNETs most commonly occur in the temporal lobe (>50%), followed by the frontal lobe (~30%). There are also reports of DNETs along the septum pellucidum.
DNETs are cortically located and usually wedge-shaped and may scallop the inner table of the skull. They demonstrate low signal on T1-weighted images (A) and high signal on T2-weighted images (B). The typical appearance is described as "bubbly" (multinodular or septated).
There may be a bright rim on FLAIR (D), but no surrounding edema or mass effect is seen. Hemorrhage is uncommon (See GRE, image C), but when it does occur, mass effect and edema may be present. Less than 1/3 enhance. About 1/3 demonstrate calcifications. The case shown here does not enhance (E and F).
Differential considerations include Taylor dysplasia, neuroepithelial cyst, and pleomorphic xanthoastrocytoma.
References
- Fernandez C et al. The usefulness of MR imaging in the diagnosis of dysembryoplastic neuroepithelial tumor in children: a study of 14 cases. AJNR Am J Neuroradiol. 24(5):829-34, 2003.
- The Requisites: Neuroradiology. Second edition, p 139.
Hi there
ReplyDeleteI am a brain tumour survivorof 5 years and have been diagnosed with an oligodendroglioma. (I live in South Africa) Initially the doctor said to me the thought it was a DNET but 3 weeks after surgery I was told it was and oligodendroglioma. What concerns me is that they took so long to come back with the results. Is there anyway I can know if I was misdiagnosed by looking at the MRIs?