Multinodular and vacuolating neuronal tumor incidentally discovered in a young man: Conventional and advanced MRI features

Abstract

Multinodular and Vacuolating Neuronal Tumor (MVNT) has been included in the most recent (2016) World Health Organization Classification of Tumors of the Central Nervous System as unique cytoarchitectural pattern of gangliocytoma. We present a case of a MVNT incidentally discovered in a 22-year old male, who presented with seizures after a head injury. Conventional MRI revealed a left parietal lesion with characteristic tiny, coalescent, well-defined, non-enhancing nodules, located in the juxtacortical white matter with partial involvement of an otherwise normal adjacent cortex and characterized by slight relative increase of the cerebral blood volume (CBV), compared to the contralateral white matter (lesional CBV/contralateral CBV = 1.112) and mild increase of choline and reduction of NAA (lesional choline/creatine ratio =1.36 and choline/NAA ratio=0.77, compared to 0.87 and 0.51, respectively). The patient fully responded to treatment with phenytoin and a follow-up MRI, six months later, showed the lesion without any substantial difference.

Multinodular and Vacuolating Posterior Fossa Lesions of Unknown Significance

“…MV-PLUS imaging features consist of the coalescence of small T1WI hypointense and T2-FLAIR hyperintense nodules in subcortical and juxtacortical areas. They are very similar to those described in MVNT, a rare and recently described brain tumor, [8][9][10][11][12][13][14] which was added in the World Health Organization Classification of Tumors of the Central Nervous System in 2016. 1,2 None of the case reports and small series published in the literature so far have reported posterior fossa MVNT.…”

Multinodular and Vacuolating Neuronal Tumor in the Brain Depth - Atypical Presentation of a New Tumor: A Case Report

“…Histologically, MVNTs lesions originates from ganglion cells, which normally present dysplastic and vacuolated, oriented perpendicular to the cortical surface [2,4]. Constituent neurons are most often of intermediate-to-large size and are randomly disposed or aligned along thin-walled blood vessels (perivascular arrangement) [4]. Some MVNTs also contain small oligodendrocyte-like elements of unclear lineage.…”

“…Mitotic activity is essentially absent, Ki-67 labeling indices do not exceed 1% in most cases [6,7]. (WHO -2016) as a unique cytoarchitectural pattern of gangliocytoma [4]. Recent studies have discovered specific immunomarkers that classifies these lesions as a new neoplasm group.…”

“…Brain Multinodular and vacuolating neuronal tumor (MVNT) is an entity that was first described by Huse et al in 2013 as a benign seizureassociated lesion with a characteristic histopathologic appearance [1]. MVNT was included in the last World Health Organization Classification of Tumors of the Central Nervous System (WHO-2016) but only as a histopathological pattern in the commentary on ganglion cell tumors, but the cIMPACT-6-Utrecht meeting opined that this lesion should be considered a distinct tumor type and could be placed within the section covering "Neuronal and mixed neuronal-glial tumors" as WHO grade I lesion [2][3][4].…”

“…MVNTs usually appear on brain MR imaging (MRI) like a cluster of variably sized nodular lesions (bubbles appearance) located predominantly in the subcortical white matter following the gyral contour. They are characteristically hyperintense on SWI and T2WI, do not suppress on FLAIR or show restricted diffusion and typically do not enhance or cause significative mass effect [2][3][4][5]. Usually clinical presentations range from asymptomatic lesion, but refractory seizures, vertigo and dysarthria have been previously described.…”