Long-Term Follow-up of Multinodular and Vacuolating Neuronal Tumors and Implications for Surveillance Imaging

Multinodular and Vacuolating Neuronal Tumors: Imaging Features, Diagnosis, and Management Challenges

Background/Objectives: Multinodular and vacuolating neuronal tumors (MNVTs) are a type of recently identified benign neuroepithelial tumor with debated malformative or neoplastic origins. This review summarizes their neuroanatomical localization, imaging, histopathology, immunohistochemistry, and diagnostic challenges. Methods: A systematic review of PUBMED/MEDLINE was performed in December 2024. Results: Of 118 screened articles, 39 were eligible, covering 299 patients. MNVTs are often asymptomatic "leave me alone" lesions, discovered incidentally, though nonspecific symptoms (59.9%) and seizures (19.7%) are reported. Immunohistochemistry reveals variable profiles, reflecting complex cellular differentiation. The characteristic "bubble-like" MRI pattern along the subcortical ribbon and superficial white matter is a reliable diagnostic feature. Rare cortical involvement and atypical band-like lesions occur. MRI signal intensity varies. Over a mean follow-up of 36 months, lesions were stable or non-recurrent, with only one case of progression. Conclusion: MVNT imaging mimics other glioneuronal lesions, but reliable diagnostic MRI features include a "bubble-clustered" appearance, lack of cortical involvement, absence of enhancement, and temporal lobe predominance. Hemodynamic and metabolic properties support the diagnosis. Most lesions remain stable, requiring no treatment. Surgical resection is reserved for cases with uncontrolled seizures or atypical locations where the diagnosis is unclear.

Multinodular and Vacuolating Neuronal Tumor-like Lesion of the Spinal Cord: Two Case Reports

We describe 2 cases of a spinal cord lesion with imaging features closely resembling those described in supratentorial multinodular and vacuolating neuronal tumor (MVNT) or infratentorial multinodular and vacuolating posterior fossa lesions of unknown significance. Multiple well-delineated nonenhancing T2-hyperintense intramedullary cystic ovoid nodules were visualized within the white matter of the spinal cord, including some immediately abutting the gray matter. No alterations in signal intensity or morphology were detected in a follow-up. Moreover, no relevant clinical symptoms attributable to the lesions were present. We describe these lesions as presumed MVNT, and we therefore use the term MVNT-like spinal cord lesions.