Presentation
Chronic tension-type headaches with no neurological symptoms. No history of seizures or loss of consciousness.
Patient Data
There is an ill-defined lesion posterosuperiorly within the right parietal lobe, composed of a cluster of predominantly coalescent nodules involving the deep cortical ribbon and subcortical white matter, corresponding to a high signal on FLAIR. It appears slightly hypointense to CSF on T2WI, hypointense on T1WI and does not demonstrate any appreciable restriction on DWI. After contrast administration, this lesion does not show any considerable enhancement.
On high-resolution axial T2-weighted images, it appears to be surrounding a couple of adjacent sulci. The overlying right parietal cortex is of normal signal intensity on all sequences with no evidence of thickening. No mass effect or surrounding edema.
Selected reconstructed high-resolution T2 and FLAIR images clearly show a cluster of hyperintense nodules (arrows) in the right parietal lobe involving the subcortical white matter with cortical sparing.
Case Discussion
Multinodular and vacuolating neuronal tumor (MNVT) of the cerebrum is a rare commonly asymptomatic tumor of mixed glial neuronal origin which is usually incidentally discovered on imaging. Added to the 2016 WHO classification of brain tumors as an exclusive pattern of gangliocytoma.
It has been linked to seizures and seizure-related disorders, presenting in adults over 35 years of age.
Characteristic findings on imaging include a cluster of punctate nodules involving the deep cortical ribbon and superficial subcortical white matter of either the parietal or temporal lobes. These nodules can sometimes coalesce, simulating a subcortical white matter mass. No associated mass-effect, edema, cortical involvement, restricted diffusion or contrast enhancement have been described in literature. They typically do not suppress on FLAIR and appear slightly hypointense to normal CSF on T2WI.
Differential diagnoses may include dilated perivascular spaces, dysembryoplastic-neuroepithelial-tumor (DNET) or focal cortical dysplasia- type II.
This case displays all these characteristic imaging features, which are readily appreciated on high resolution images.
These lesions have been described as "leave me alone" lesions, requiring no biopsy or resection. Typically, MRI surveillance is recommended.
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