Multinodular and vacuolating posterior fossa lesions of unknown significance: a long-term observational study and literature review.

Multinodular and vacuolating neuronal tumor of the cerebrum (MVNT) is a rare tumefactive lesion requiring differentiation from glial tumors. Multinodular and vacuolating posterior fossa lesions of unknown significance (MV-PLUS) were initially reported in 2019 as posterior fossa lesions with characteristics similar to MVNT. MV-PLUS is often considered as a "leave-me-alone lesion" not necessitating surgical intervention. However, no studies have reported on MV-PLUS with long-term follow-up. In this report, we presented six new cases of MV-PLUS and reviewed existing literature on the condition. The median observation period for our cases was 93 months (range 79-124 months), significantly longer than previously reported. None of the patients underwent surgical treatment or showed any imaging changes during the observation period. We emphasize the importance of understanding the imaging characteristics of MV-PLUS to accurately differentiate these infratentorial lesions and avoid unnecessary surgical interventions.