Neurosurgery notes/Tumours/Gliomas, Glioneuronal Tumors, and Neuronal Tumors/Glioneuronal and neuronal tumours/Multinodular and vacuolating neuronal tumour (MVNT)

Multinodular and vacuolating neuronal tumour (MVNT)

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Glioneuronal and neuronal tumours

Definition

  • Essential:
    • Multinodularity AND
    • Neuronal cytological features or tumour cell immunoreactivity for synaptophysin HuC/HuD, or non-phosphorylated 200-kDa NFP AND
    • Absence of mitotic activity AND
    • Tumour cell / matrix vacuolation (but may be minimal)
  • Desirable:
    • Immunoreactivity for 0LIG2 and intemexin A
    • Absence of NeuN or chromogranin expression
    • МАРК pathway-activating abnormalities

General

  • Aka: Diffuse gangliocytoma (don’t use)

WHO grade

  • Grade 1

Number

  • Median: 42 years
    • Few paediatric cases
  • M:F ratio is 1.5:1

Genetic

  • Somatic gene abnormalities that activate RAS/RAF/MAPK signalling have been consistently identified, with MAP2K1 and BRAF mutations (other than BRAF V600E) being recurrently identified

Localisation

  • Supratentorial
    • On the inner surface of otherwise normal cortex

Clinical features

  • Seizure 60%
    • Complex partial type with or without secondary generalization
  • Non-focal headache 10-15%
  • Most are detected incidentally on imaging.

Imaging

  • Comprised multiple discrete round/ovoid nodules
  • Ranging from 1 to 5 mm in diameter distributed along the subcortical ribbon
  • These small nodules are hyperintense on T2w
  • Generally do not supress on FLAIR.
    • Described at 3T field strength, Lecler et al. proposed that a focus of central FLAIR suppression within the vacuolated areas can increase diagnostic confidence
  • No restricted diffusion
  • Has blooming artefact with a clear margin to adjacent tissues
  • Lesion stability on surveillance imaging
A close-up of a brain scan AI-generated content may be incorrect.
A 39-year-old woman with a 26-year history of occasional seizures.
T2w (A, B) demonstrates a left para-midline, multi-cystic lesion centred on the subcortical white matter of the left cingulate gyrus.
The lesion demonstrates no enhancement on T1w-CE (C) and the cystic regions suppress on FLAIR (D)

Histopathology

Macroscopic

  • Multiple discrete or coalescent grey nodules involving the
    • Deep cortex
    • Grey matter-white matter junction
    • Subcortical white matter

Microscopic

  • Neuroepithelial cells with stromal vacuolation in a nodular formation within the deep cortex and adjacent white matter
  • MVNTs can be associated with regional cortical disorganization and hippocampal sclerosis
Fig. 4 Multinodular and vacuolating neuronal tumor is a benign tumor comprising monomorphous neuronal elements in discrete and coalescent nodules, with vacuolar changes both in tumor cells and the neuropil. (A) Multinodular appearance (H&E, x40). (B) Vacuolar change in tumor cells and in neuropil (H&E, x200).
Multinodular and vacuolating neuronal tumor is a benign tumor comprising monomorphous neuronal elements in discrete and coalescent nodules, with vacuolar changes both in tumor cells and the neuropil. (A) Multinodular appearance (H&E, ×40). (B) Vacuolar change in tumor cells and in neuropil (H&E, ×200).

Prognosis

  • Benign nature of this lesion
    • ‘Do-not-touch’ lesion with typical radiological appearances precluding the need for biopsy