Dysembryoplastic neuroepithelial tumor (DNET) associated with dysgenesis of the corpus callosum

Dysembryoplastic neuroepithelial tumour (DNET) is a unique type of low-grade glioneuronal tumour, usually presenting with childhood or adolescent epilepsy refractory to medical treatment. DNETs are slow-growing tumours arising from the cerebral cortex, usually involving an entire gyrus or a wedge-shaped part of a cerebral lobe. Pathologically, typical DNETs comprise the tumour core surrounded by the rim of dysplastic cortex; this rim of dysplastic cortex is regarded as highly epileptogenic. Complete resection of the tumour is crucial for seizure control. DNET appears on CT as a low-attenuating cortically based-based mass with extension into the subcortical area. MRI is the imaging modality of choice for diagnosing DNET. It usually demonstrates a bubbly appearance with low signal intensity on T1W images and high signal on T2W images and FLAIR, without noticeable enhancement. Poor enhancement is a common feature that distinguishes DNET from gangliogliomas, which usually show intense enhancement. The differential diagnosis in this particular case is between DNET and a low-grade glioma. The imaging characteristics and presentation of the patient align more favourably with the former.

Dysgenesis of the corpus callosum represents an in utero-utero developmental anomaly characterised by incomplete development of the corpus callosum development. It is associated with many other CNS anomalies, including Chiari II malformation, Dandy-Walker spectrum, and grey matter heterotopia, among others. However, there is still no clearly proven association between this anomaly and DNET exists.