Presumptive diagnosis of multinodular vacuolating tumor: "more than meets the eye!"

A rare cause of adult's epileptic crisis: Infratentorial multinodular and vacuolating neuronal tumor

Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a rare and benign lesion which has been recently included in World Health Organization Classification of the central nervous system tumors. Another entity of lesions would present the same radiological characteristics; however, it would be in the posterior fossa, hence its name: infratentorial multinodular and vacuolating neuronal tumor. They are frequently characterized by the presence of cystic (or cyst-like) nodular lesions and may show cortical involvement. They mainly can be differentiated from other cystic entities, by their clustered and unchanging nature over time. We present the case of a 54-year-old patient who has consulted for epileptic seizures. Magnetic Resonance Imaging showed a multicystic-looking mass involving the vermis and the left cerebellar hemisphere that had no changes at follow-up in the last year suggestive of infratentorial multinodular and vacuolating neuronal tumor.

Infratentorial Multinodular and Vacuolating Neuronal Tumor or Multinodular and Vacuolating Posterior Fossa Lesions of Unknown Significance? Clinico-Radiologic Findings from 2 Cases

BACKGROUND

Infratentorial multinodular lesions resembling multinodular and vacuolating neuronal tumor of the cerebrum (MVNT) have been indicated in literature with 2 different names reflecting alternative perspectives: multinodular and vacuolating posterior fossa lesions of unknown significance (MV-PLUS), suggesting that these lesions may belong to a new entity, and MVNT of the brain, assuming that they actually correspond to infratentorial MVNT. Because of the limited number of cases reported and the absence of histopathologic data, it is unclear which denomination should be used.

CASES DESCRIPTION

Two patients, a 41-year-old man (case 1) suffering headache and a 44-year-old man (case 2) with vertigo, underwent magnetic resonance imaging (MRI) examination. MRI showed, in both cases, multinodular lesions involving the vermis, broadly extending to the superior part of the right cerebellar hemisphere in case 1, and involving the superior paravermian part of the left cerebellar hemisphere in case 2. The follow-up period was 3 years in case 1 and 14 years in case 2.

CONCLUSIONS

Infratentorial lesions show nodules with cystic or cyst-like signal intensity on MRI, a feature infrequently reported in supratentorial MVNT, and may involve the cortex. No variations were noted during a prolonged follow-up supporting the benign behavior of these lesions.