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Updated: May 23, 2025
Multiple-mouse Neuroanatomical Magnetic Resonance Imaging
Published on: February 27, 2011
The Mickey Mouse's hand sign in brain MRI points out multinodular and vacuolating neuronal tumors in mesial temporal
Valerio Frazzini1,2, Bertrand Mathon3,2, Natalia Shor2,4
1Epilepsy and EEG Unit, Department of Neurology, Pitié-Salpêtrière Hospital, Reference Center for Rare Epilepsies, ERN-EPICARE, AP-HP, 75013, Paris, France.
Purpose:
Multinodular and vacuolating neuronal tumor (MVNT) is a rarely diagnosed neoplastic lesion often associated with adult-onset focal seizures. In some situations, atypical MRI features of MVNT may mimic other long-term epilepsy associated tumors (LEATs) or diffuse low-grade gliomas. In such a context, the identification of distinct clinical markers is recommended.
Methods:
We retrospectively analyzed the neuroimaging features of histologically confirmed MVNT lesions of our epilepsy surgery cohort. All the identified MVNT patients had a mesial temporal lobe location. The MRI features from the MVNT population were compared to those from non-MVNT lesions randomly selected in our cohort. Non-MVNT lesions consisted of (i) other tumoral lesions belonging to LEATs group, (ii) infiltrative tumoral lesions such as grade 2, IDH-mutant Gliomas, and (iii) non-tumoral, highly epileptogenic lesions, such as hippocampal sclerosis.
Results:
MRI analysis of patients with MVNT noticed an unusual FLAIR hyperintense signal extending from the uncus to the anterior white commissure through the sublenticular region. This neuroimaging abnormality visually mimicked "Mickey Mouse's hand" on coronal plane. The "Mickey Mouse's hand" sign was identified in 6 patients out of 9 (66.7%) MVNT patients. We did not identify the Mickey Mouse's hand sign in other control lesions (0/11 ganglioglioma, 0/11 glioma, 0/150 hippocampal sclerosis), except in one patient with dysembryoplastic neuroepithelial tumors (DNET) (1/15; 6.7%). All patients showing the "Mickey Mouse's hand" sign were seizure-free after surgery.
Conclusions:
The Mickey Mouse's hand sign represents a straightforward and easy-to-remember neuroimaging feature, that does not require advanced MRI sequences and that could help clinicians facing mesial temporal lesions to rapidly raise the suspicion of MVNT diagnosis.
Insights
The "Mickey Mouse
Area of Science:
- Neurology
- Neuroradiology
- Epileptology
Background:
- Multinodular and vacuolating neuronal tumor (MVNT) is a rare cause of adult-onset focal seizures.
- Atypical MRI findings of MVNT can mimic other long-term epilepsy associated tumors (LEATs) or diffuse low-grade gliomas.
- Distinct clinical markers are needed for accurate MVNT diagnosis.
Purpose of the Study:
- To identify distinct neuroimaging markers for Multinodular and vacuolating neuronal tumor (MVNT).
- To differentiate MVNT from other mesial temporal lobe lesions, including LEATs, gliomas, and hippocampal sclerosis.
Main Methods:
- Retrospective analysis of neuroimaging features in a cohort of histologically confirmed MVNT patients.
- Comparison of MRI features of MVNT lesions with non-MVNT lesions (LEATs, gliomas, hippocampal sclerosis).
Main Results:
- An unusual FLAIR hyperintense signal, termed the "Mickey Mouse's hand" sign, was observed in 66.7% of MVNT patients.
- This sign was highly specific for MVNT, with only one case of dysembryoplastic neuroepithelial tumor (DNET) showing a similar feature.
- All patients with the "Mickey Mouse's hand" sign achieved seizure freedom post-surgery.
Conclusions:
- The "Mickey Mouse's hand" sign is a simple and memorable neuroimaging feature for identifying MVNT.
- This sign aids clinicians in rapidly suspecting MVNT in patients with mesial temporal lesions.
- The presence of the "Mickey Mouse's hand" sign correlates with successful surgical outcomes for epilepsy.
