NF2 and neoplasm: It has been shown that patients with tumors limited to the central nervous system have significantly enriched ctDNA in CSF.8 Interestingly, we were able to detect in CSF an NF2 mutation not found in the tumor, a feature already reported in brain tumor,8 which may be due to the tumor heterogeneity.9 Further studies are required to assess the sensitivity and the interest of cfDNA analysis to address some limitations of tissue-based genetics.10