Multinodular and Vacuolating Neuronal Tumor: A Rare Seizure-associated Entity

Case report: Rare case of multinodular and vacuolar neuronal tumors in the cerebellum

Multinodular and vacuolar neuronal tumor (MVNT) is a rare and benign neuroepithelial tumor. Most reports describe tumors located in the cerebral hemisphere. A literature review found that 15 cases were located in the posterior cranial fossa, but all lacked pathological evidence. In this case, a patient sought medical attention due to insomnia and irritability. Neuroepithelial tumors were found in the imaging, and the patient underwent radiation therapy. Three years later, malignant tumors were found upon imaging examination. After surgical resection and pathological testing, MVNT occurring in the cerebellum was diagnosed. MVNT is rare in the cerebellum, and direct imaging diagnosis becomes difficult after treatment. Therefore, our report of this case helps to further accurate understanding of the imaging, pathological, and molecular genetic changes occurring before and after MVNT treatment, and will improve the accuracy of pre-treatment diagnosis and reduce the likelihood of overtreatment.

The landscape of common genetic drivers and DNA methylation in low-grade (epilepsy-associated) neuroepithelial tumors: A review

Low-grade neuroepithelial tumors (LNETs) represent an important group of central nervous system neoplasms, some of which may be associated to epilepsy. The concept of long-term epilepsy-associated tumors (LEATs) includes a heterogenous group of low-grade, cortically based tumors, associated to drug-resistant epilepsy, often requiring surgical treatment. LEATs entities can sometimes be poorly discriminated by histological features, precluding a confident classification in the absence of additional diagnostic tools. This study aimed to provide an updated review on the genomic findings and DNA methylation profiling advances in LNETs, including histological entities of LEATs. A comprehensive search strategy was conducted on PubMed, Embase, and Web of Science Core Collection. High-quality peer-reviewed original manuscripts and review articles with full-text in English, published between 2003 and 2022, were included. Results were screened based on titles and abstracts to determine suitability for inclusion, and when addressed the topic of the review was screened by full-text reading. Data extraction was performed through a qualitative content analysis approach. Most LNETs appear to be driven mainly by a single genomic abnormality and respective affected signaling pathway, including BRAF p.V600E mutations in ganglioglioma, FGFR1 abnormalities in dysembryoplastic neuroepithelial tumor, MYB alterations in angiocentric glioma, BRAF fusions in pilocytic astrocytoma, PRKCA fusions in papillary glioneuronal tumor, between others. However, these molecular alterations are not exclusive, with some overlap amongst different tumor histologies. Also, clustering analysis of DNA methylation profiles allowed the identification of biologically similar molecular groups that sometimes transcend conventional histopathological classification. The exciting developments on the molecular basis of these tumors reinforce the importance of an integrative histopathological and (epi)genetic classification, which can be translated into precision medicine approaches.

Multinodular and vacuolating neuronal tumor of the cerebrum: Two cases and review of the literature

BACKGROUND

Multinodular and vacuolating neuronal tumor (MVNT) recently described as a purely neuronal tumor. Although its nature as a genuine tumor is controversial, this new entity assumed benign lesion and mostly affecting adults. Herein, we introduce two cases of MVNT presumed low grade glial tumor (LGG) and focal cortical dyplasia (FCD) as a differential diagnosis.

CASE DESCRIPTION

Case 1 has admitted to our hospital with headache which frequency and severity has increased within two months. Radiological examination revealed hyperintensity on T2-WI and T2 FLAIR images. Microsurgical resection was performed and histopathological findings were compatible with MVNT instead of low grade glial tumor as we thought. Case 2, who presented at our hospital with one episode seizure. MRI showed T2 hyperintensity and T1 hypointensity without contrast enhancement. We suspected FCD, thus performed microsurgical gross total resection with frontal craniotomy. Pathological findings confirmed MVNT as a diagnosis. Both cases were discharged on the 3rd day after surgery without any complications and with no regrowth of tumor at the 9-months and 3-months follow-up respectively.

CONCLUSIONS

Radiological hallmarks may be helpful to prevent from aggressive treatment in case of patient is asemptomatic. Nevertheless further studies are necessary for the adoption of 'wait and see' philosophy and give a verdict about benign nature of these tumors.

Multinodular and vacuolating neuronal tumor associated with focal cortical dysplasia in a child with refractory epilepsy: a case report and brief review of literature

Multinodular and vacuolating neuronal tumor (MVNT) is a rare newly identified benign lesion, firstly included in the World Health Organization classification of tumors of the central nervous system in 2016, whose neoplastic or dysplastic nature remains unclear but with a distinctive cytoarchitectural pattern and radiological features. It is usually discovered as late-onset refractory epilepsy, headache related, or an incidental lesion of adulthood. As it is typically a stable disease, many opt for follow-up, as long as it keeps remaining asymptomatic, leaving surgery for refractory epilepsy, neurological deficits, or intracranial hypertension symptoms. A subtotal or complete resection seems to control seizures and neurological manifestations. We herein present the case of a child with refractory epilepsy related to MVNT and focal cortical dysplasia, a dual pathology case in a less frequent age group and without the typical radiological imaging. We report its radiologic features, histologic description, and management, and we present a brief literature review on MVNT focusing on the pediatric cases reported. MVNT should now be another probable low-grade epilepsy-associated lesion (LEAT) in patients of all ages, with a benign and stable course as it constitutes a curable cause of focal epilepsy. As all the refractory cases, surgery should be indicated after a comprehensive evaluation of a multidisciplinary epilepsy surgery team.

Advanced multiparametric magnetic resonance imaging of multinodular and vacuolating neuronal tumor

BACKGROUND AND PURPOSE

Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a rare brain lesion with suggestive imaging features. The aim of our study was to report the largest series of MVNTs so far and to evaluate the utility of advanced multiparametric magnetic resonance (MR) techniques.

METHODS

This multicenter retrospective study was approved by our institutional research ethics board. From July 2014 to May 2019, two radiologists read in consensus the MR examinations of patients presenting with a lesion suggestive of an MVNT. They analyzed the lesions' MR characteristics on structural images and advanced multiparametric MR imaging.

RESULTS

A total of 64 patients (29 women and 35 men, mean age 44.2 ± 15.1 years) from 25 centers were included. Lesions were all hyperintense on fluid-attenuated inversion recovery and T2-weighted imaging without post-contrast enhancement. The median relative apparent diffusion coefficient on diffusion-weighted imaging was 1.13 [interquartile range (IQR), 0.2]. Perfusion-weighted imaging showed no increase in perfusion, with a relative cerebral blood volume of 1.02 (IQR, 0.05) and a relative cerebral blood flow of 1.01 (IQR, 0.08). MR spectroscopy showed no abnormal peaks. Median follow-up was 2 (IQR, 1.2) years, without any changes in size.

CONCLUSIONS

A comprehensive characterization protocol including advanced multiparametric magnetic resonance imaging sequences showed no imaging patterns suggestive of malignancy in MVNTs. It might be useful to better characterize MVNTs.

Multinodular and vacuolating neuronal tumor (MVNT): A presumably incidental and asymptomatic case in an intractable epilepsy patient

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Multinodular vacuolating neuronal tumor (MVNT) was initially reported as epilepsy-related brain tumor.

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MVNT can exist as incidental and asymptomatic lesions in some cases.

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It is not always necessary to perform surgical resection of MVNT even in patients with epilepsy.

Introduction

Multinodular and vacuolating neuronal tumor (MVNT) had been initially described as an epilepsy-related brain tumor, but recent studies demonstrated it could be found incidentally in non-epilepsy patients.

Case report

A 33-year-old woman with intractable post-encephalitis epilepsy presented a cluster of multinodular T2 hyperintensity in the left temporal lobe, which was very similar to the characteristics of MVNT. Long-term video electroencephalogram demonstrated that the habitual seizures were originated from bilateral temporal area and the interictal epileptic discharges were seen multifocally, although the lesions with MVNT appearance were localized in the left temporal lobe. It was presumed that the epilepsy in this patient was due to encephalitis in the past, and the link between the lesions and the epilepsy in this patient seemed weak.

Conclusion

Although MVNT had been considered as an epilepsy-related brain tumor, we suggest it is not necessarily preferable to perform surgical resection of MVNT even on patients with epilepsy, unless epileptic foci are highly related to MVNT.

A review of recently described genetic alterations in central nervous system tumors

Advances in molecular profiling of central nervous system tumors have enabled the development of classification schemes with improved diagnostic and prognostic accuracy. As such, the 2016 World Health Organization Classification of Tumors of the Central Nervous System (WHO 2016) introduced a paradigm shift in the diagnosis of brain tumors. For instance, integrated assessment incorporating both histologic features and genetic alterations was introduced into the diagnostic framework of gliomas. IDH1/2 mutation status now represents the most important initial stratifier of diffuse gliomas in adults, although rarer subtypes within the IDH-wildtype category continue to be elucidated. Medulloblastomas and other embryonal neoplasms were also genetically defined and segregated based on molecular subtypes, and 1 molecular subtype of ependymoma was added. In this review, we summarize the rapidly evolving spectrum of recurrent genetic alterations described in central nervous system tumor entities since the publication of the WHO 2016.

Clinicopathological and molecular analysis of multinodular and vacuolating neuronal tumors of the cerebrum

Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a recently recognized rare neuronal tumor, and its pathogenesis is unclear. We analyzed 7 cases of histologically typical MVNT: 6 were adults (mean age, 43.0 years [range, 23-56 years]) and 1 was a child (age, 10 years). The most common symptoms were seizures (n = 4) and headache (n = 2). The tumors were supratentorial (temporal, 5; frontal lobes, 2) in origin as reported. Vacuolated tumor cells were robustly positive for α-INA and Olig2 and at least partly positive for synaptophysin and MAP2, but negative for Neu-N, nestin and CD34. GFAP and vimentin were expressed in reactive astrocytes but not in tumor cells. Negative results were obtained for p53, IDH-1, BRAF^V600E, H3 K27M, EGFR, Lin28A, and L1CAM. ATRX, BRG1, INI-1, and TMHH were retained. The Ki-67 labeling index was very low (<1%), and pHH3 revealed no mitotic figure. Ultrastructural features of tumor cells were comparable with those of immature neuronal cells, with several intracytoplasmic myelin-like autophagosomes and pericellular vacuolization. No IDH1/IDH2 and BRAF^V600E mutations were found upon direct sequencing. Whole-exome sequencing revealed FGFR2-ZMYND11 gene fusion in 1 case. After gross total resection, all patients were alive without seizures. There was no tumor recurrence during an average period of 68 months (range, 23-101 months). The analysis of 7 typical cases of MVNT suggested that these lesions may be clonal tumors because FGFR2-ZMYND11 fusion was found (1 case).

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

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 neuronal tumor: A case report and literature review

Background:

Multinodular and vacuolated neuronal tumor (MVNT) is a benign neuronal tumor that is newly recognized as architectural appearance that may be related to ganglion cell tumors in 2016 World Health Organization Classification of Tumors of the Central Nervous System. Herein, we report a case of MVNT in a 60-year-old man with a thorough literature review.

Case Description:

A 60-year-old male was pointed out the presence of intracerebral neoplasm located in left frontal lobe by a comprehensive medical examination. We suspected dysembryoplastic neuroepithelial tumors and proposed him to wait and see, but he wished to undergo surgery for diagnosis. We performed en bloc resection and pathological findings were consistent with MVNT. He was discharged on the 8^th day after the operation without any complications. He remained stable without recurrence at the 16-month postoperative follow-up.

Conclusions:

Further studies may be helpful to fully understand the radiological and histological findings of MVNT development. As a result, we will be able to prevent the aggressive treatment if we established their major features.

Multinodular and vacuolating neuronal tumors in epilepsy: dysplasia or neoplasia?

Multinodular and vacuolating neuronal tumor (MVNT) is a new pattern of neuronal tumour included in the recently revised WHO 2016 classification of tumors of the CNS. There are 15 reports in the literature to date. They are typically associated with late onset epilepsy and a neoplastic vs. malformative biology has been questioned. We present a series of ten cases and compare their pathological and genetic features to better characterized epilepsy‐associated malformations including focal cortical dysplasia type II (FCDII) and low‐grade epilepsy‐associated tumors (LEAT). Clinical and neuroradiology data were reviewed and a broad immunohistochemistry panel was applied to explore neuronal and glial differentiation, interneuronal populations, mTOR pathway activation and neurodegenerative changes. Next generation sequencing was performed for targeted multi‐gene analysis to identify mutations common to epilepsy lesions including FCDII and LEAT. All of the surgical cases in this series presented with seizures, and were located in the temporal lobe. There was a lack of any progressive changes on serial pre‐operative MRI and a mean age at surgery of 45 years. The vacuolated cells of the lesion expressed mature neuronal markers (neurofilament/SMI32, MAP2, synaptophysin). Prominent labelling of the lesional cells for developmentally regulated proteins (OTX1, TBR1, SOX2, MAP1b, CD34, GFAPδ) and oligodendroglial lineage markers (OLIG2, SMI94) was observed. No mutations were detected in the mTOR pathway genes, BRAF, FGFR1 or MYB. Clinical, pathological and genetic data could indicate that MVNT aligns more with a malformative lesion than a true neoplasm with origin from a progenitor neuro‐glial cell type showing aberrant maturation.