Tumors mimicking supratentorial ependymomas

Supratentorial ependymomas without ZFTA or YAP1 fusions (on chromosome 11) are an undefined entity, and it is unclear what these samples represent. By DNA methylation analysis, these samples often cluster with other entities such as high-grade gliomas and embryonal tumors. As one example, a retrospective methylation analysis of supratentorial brain tumors identified a group of tumors distinct from supratentorial ependymoma that harbor recurrent PLAGL1 fusions.[186] The histological lineage of these PLAGL1-altered tumors is not yet clear. Nineteen of the 32 tumors (59%) had previously been reported as ependymomas. Caution should be taken when diagnosing a supratentorial ependymoma that does not harbor a fusion involving chromosome 11.[28,170,187]