CDKN2B and pleomorphic xanthoastrocytoma: Pleomorphic xanthoastrocytoma (PXA) is an astrocytic tumor (CNS WHO grade 2 or 3), typically harboring BRAF p. V600E point mutation associated with homozygous deletion of CDKN2A and/or CDKN2B. Its incidence is <1% (Ostrom et al., 2022); it arises in children and young adults with a median age of 20 years, but it may also occur in older patients (Perkins et al., 2012).