Hippocampal DNET

A DNET is a benign intracortical mass, typically multinodular in appearance, with a ‘bubbly appearance’. It coexists with an area of cortical dysplasia, and is characteristically the cause of intractable partial seizures. It demonstrates essentially no growth over time, although very gradual increase in size has been described.

Location
hippocampal formation and amygdala (most common) – (see case 1)
– caudate nucleus
– septum pellucidum

DDx
Medial temporal lobe

– Tumours (in order of decreasing frequency)
Ganglioglioma
– low grade astrocytoma
Pleomorphic xanthoastrocytoma

– Cysts
– neuroepithelial cyst
– choriod fissure cyst
– Other
– herpes simplex encephalitis – usually some bilateral changes, and different presentation.
– limbic encephalitis- usually some bilateral changes, and different presentation.
mesial temporal sclerosis
– cortical dysplasia

References:
– Neuroradiology: The Requisites
– Brain: Diagnostic imaging by Osborn

For more images of the same case please visit here.
For more on DNET please visit Radiopaedia.org here.

Credit: Dr Frank Gaillard