posterior fossa ependymoma posterior fossa group B ependymoma https://github.com/monarch-initiative/mondo/issues/8567 https://www.malacards.org/card/posterior_fossa_group_b_ependymoma DOID:0081255 NCIT:C186451 MONDO:0956993 A posterior fossa ependymoma that arises in the posterior fossa with characteristic DNA methylation patterns including retention of nuclear H3 p.K28me3 (K27me3) expression, absence of CpG island hypermethylation, absence of global DNA hypomethylation, and absence of EZHIP overexpression. GARD:0026780