NF2 and meningioma: Monosomy 22/del(22q) in association or not with various mutations of the NF2 gene, is by far the most frequent cytogenetic event, potentially occurring at the early stages of the disease; however, other isolated chromosomal alterations and gene mutations, together with more complex karyotypes, have also been reported in meningiomas at relatively high frequencies, usually in association with a more aggressive tumor behavior [4].