For example, double-allele NF1 inactivation is required for the development of CALMs and neurofibromin, and P53 mutation is also necessary for the formation of malignant peripheral nerve sheath tumors.[1] In this case, postoperative pathology revealed a spindle cell tumor (nonmalignant), so malignant invasion of the skull can be ruled out. The gene discussed is NF1; the disease is spindle cell neoplasm.