These observations might tentatively be linked to peculiar aspects of the maturation and differentiation of Schwann cells in neurofibromas, which might translate into different concentrations of the cytoplasmatic content of neurofibromin, arising from differences in the morphological expression of genetic alterations of the NF1 gene (monoallelic or biallelic) [2–6] and the neural microenvironment [7]. The gene discussed is NF1; the disease is plexiform neurofibroma.