Multinodular and vacuolating neuronal tumor of the cerebrum
Sudden onset left sided visual loss lasting for 5 minutes with an associated collapse, followed by a headache. Examination at the time of presentation was normal. 20-pack-year smoking history and a family history positive for stroke. CT brain and CT intracranial angiogram were normal. Ultrasound of the carotid and vertebral arteries was also normal.
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T2 MRI displays a cluster of hyperintense nodules in the deep cortical ribbon and subcortical white matter in the posterosuperior right parietal lobe. The nodules are of varying size, coalescing at some points. There is no suppression on FLAIR. There is no mass effect or restricted diffusion. They do not display susceptibility on gradient echo imaging.
These findings are highly suggestive of multinodular and vacuolating neuronal tumor of the cerebrum (MVNT). The lesion has remained stable over a period of 14 months, and the patient is under MRI surveillance.
Multinodular and vacuolating neuronal tumor of the cerebrum (MVNT) is a recently recognized “leave-alone” neuronal lesion. It is characterized by typical MR imaging characteristics and a typical cytoarchitectural pattern of neuroepithelial cells organized in a nodular formation, with stromal vacuolation and glial/neuronal differentiation 1.
It was first described in 2013 by Huse 1 and has recently been included in the 2016 World Health Organization classification of brain neoplasms as a grade 1 lesion 2. It is a benign-behaving lesion that is likely to represent a malformative/dysplastic process rather than a true neoplasm.
If a case has typical imaging characteristics, biopsy can be avoided. Treatment is not indicated unless a specific symptom exists (such as resective surgery for seizure). Surveillance imaging is adequate and these lesions invariably remain stable over time 3.
MVNT appears on MRI as:
- multiple variably-sized nodules measuring 1-5 mm that are sharply demarcated and may appear round or oval and can be discrete, clustered or coalescent 3
- nodules are T1 iso/hypointense, T2 hyperintense and do not suppress on FLAIR 3
- nodules occur within the deep cortical ribbon and subcortical and juxtacortical white matter and can occur in any supratentorial lobe 3
- On high resolution 3T imaging, it has been suggested that a central FLAIR hypointense signal and central punctiform T1 hyperintensity can be noted, possibly due to protein or solid content 4
MVNT has been associated with seizures in the temporal lobe however is often incidentally detected after presentation with a non-specific headache or other reason 3.
Given the focal cystic spaces that typify MVNT, the differential diagnosis includes dysembryoplastic neuroepithelial tumor (DNET), ganglioglioma, focal cortical dysplasia, and enlarged perivascular spaces.
Key learning points:
- MVNT is a "leave-alone" lesion that is generally felt to represent an incidental finding
- characterized by clusters of T2 hyperintense nodules in the juxtacortical white matter
- no biopsy or treatment is indicated; surveillance imaging is however recommended
- 1. Huse JT, Edgar M, Halliday J, Mikolaenko I, Lavi E, Rosenblum MK. Multinodular and vacuolating neuronal tumors of the cerebrum: 10 cases of a distinctive seizure-associated lesion. (2013) Brain pathology (Zurich, Switzerland). 23 (5): 515-24. doi:10.1111/bpa.12035 - Pubmed
- 2. Louis DN, Perry A, Reifenberger G, von Deimling A, Figarella-Branger D, Cavenee WK, Ohgaki H, Wiestler OD, Kleihues P, Ellison DW. The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary. (2016) Acta neuropathologica. 131 (6): 803-20. doi:10.1007/s00401-016-1545-1 - Pubmed
- 3. Nunes RH, Hsu CC, da Rocha AJ, do Amaral LLF, Godoy LFS, Watkins TW, Marussi VH, Warmuth-Metz M, Alves HC, Goncalves FG, Kleinschmidt-DeMasters BK, Osborn AG. Multinodular and Vacuolating Neuronal Tumor of the Cerebrum: A New "Leave Me Alone" Lesion with a Characteristic Imaging Pattern. (2017) AJNR. American journal of neuroradiology. 38 (10): 1899-1904. doi:10.3174/ajnr.A5281 - Pubmed
- 4. Lecler A, Chauvet D, Biassette HA, Savatovsky J. Multiparametric Imaging Improves Confidence in the Diagnosis of Multinodular and Vacuolating Neuronal Tumor of the Cerebrum. (2018) AJNR. American journal of neuroradiology. 39 (2): E32-E33. doi:10.3174/ajnr.A5425 - Pubmed