1. Definition and historical context.
Multinodular and vacuolating neuronal tumor of the cerebrum is a recently reported benign, mixed glial neuronal lesion, that is included in the 2016 updated World Health Organization classification of brain neoplasms, as a unique cytoarchitectural pattern of gangliocytoma.
2. 2016 WHO classification of tumors of the central nervous system.
The 2016 World Health Organization Classification of Tumors of the Central Nervous System is both a conceptual and practical advance over its 2007 predecessor (Fig. 1)
- WHO classification uses molecular parameters in addition to histology to define many tumor entities.
- Approximate the naming conventions of the hematopoietic/lymphoid pathology community.
- CNS tumor diagnoses should consist of a histopathological name followed by the genetic features.
- Major restructuring of the diffuse gliomas, medulloblastomas and other embryonal tumors.
- Incorporates new entities that are defined by both histology and molecular features.
- Newly recognized neoplasms, and deleted some entities.
3. Epidemiology and clinical presentation.
The epidemiology of these tumors is unknown as they have only been recently described and many are asymptomatic and thus likely undiagnosed.
Many of these lesions are probably asymptomatic and may be found incidentally on imaging for other reasons, however, in some individuals these tumors are associated with epileptic disorders.
On the other hand it´s also important to konw that recent case studies demonstrated MVNT could often be found incidentally in non-epilepsy patients and therefore invasive examination or treatment should be carefully considered.
4. MVNT histopathological substrate.
MVNT are currently considered a tumor and a growth pattern of gangliocytomas (WHO grade I).
They present similar histopathologic features, showing neuroepithelial cells with conspicuous stromal vacuolation arranged in nodules principally within the deep cortical ribbon and superficial subcortical white matter.
These dysplastic cells typically orient perpendicular to the cortical surface, which correlates well with the radiologic appearance of clusters or a linear array of juxtacortical nodules (Fig. 2)
Immunostaining is positive for synaptophysin, HuC/HuD neuronal antigens and p62. (Fig. 3)