With the exception of bilateral vestibular schwannomas (pathognomonic of “NF2-related schwannomatosis”) (Figure 12) (Table 8), the isolated/solitary schwannoma, as it occurs with its counterpart within the spectrum of NF1-related disorders (i.e., the neurofibroma), should/could be regarded as a manifestation of mosaic NF2/SMARCB1/LZTR1 or 22q-related-schwannomatoses (or schwannoma predisposing syndromes) and thus molecular genetic testing should be performed on the referred specimen(s) (Table 7). This evidence concerns the gene SMARCB1 and plexiform neurofibroma.