MYCN and subependymoma: The WHO 2021 classification of spinal cord ependymomas includes spinal ependymoma (SP-EPN), spinal ependymoma with N-Myc (also known as MYCN) amplification (SP-MYCN), myxopapillary ependymoma (MPE), subependymoma (SE), and neurofibromatosis 2 (NF2)-mutated variants (with losses on chromosome 22q).