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

Abstract Background Infratentorial multinodular lesions resembling Multinodular and Vacuolating Neuronal Tumor of the cerebrum (MVNT) have been indicated in literature with two 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. Due to the limited number of cases reported and the absence of histopathological data, it is presently uncertain which denomination should be used. Cases description Two patients, a 41-years old man (case 1) suffering headache and a 44-years old man (case 2) with vertigo, performed magnetic resonance examination. MR showed, in both cases, multi-nodular lesions involving the vermis, broadly extending to the superior part of the right cerebellar hemisphere in case 1, while involving the superior para-vermian 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 evolutivity was noted during a prolonged follow-up supporting the benign behavior of these lesions.