RELA and subependymoma: The 2016 World Health Organization (WHO) Classification of Tumors of the CNS categorizes them into four subtypes: subependymoma and myxopapillary ependymoma (grade I), ependymoma (grade II), ependymoma RELA (v-rel avian reticuloendotheliosis viral oncogene homolog A) fusion-positive (grade II or III), and anaplastic ependymoma (grade III) [12, 58].