Presentation
A male patient presented with recurrent fits.
Patient Data
A focal cortically-based area is noted in the posterior temporal lobe on the right with abnormal signal changes (high on T2WI and FLAIR, iso on T1WI). It is associated with an expansion of the gyri and containing multiple small cysts (a bubbly appearance). It elicits mixed signal intensity with a well-defined rim of high signal around on FLAIR sequences. This T2/FLAIR hyperintense rim is specific for DNET and termed bright rim sign. No enhancement showed at post-Gadolinium injection. No significant mass effect nor surrounding vasogenic edema.
Case Discussion
Dysembryoplastic neuroepithelial tumors (DNET) are benign (WHO grade I) slow growing glioneuronal tumors arising from either cortical or deep grey matter. They characteristically cause intractable partial seizures (temporal lobe epilepsy).