Although EWS is a type of “small round blue cell tumor,” it is unrelated to medulloblastoma, CNS embryonal tumors, or embryonal tumors with multilayered rosettes, C19MC altered.1 Because therapy for EWS differs considerably from embryonal CNS tumors, correct diagnosis is critical and typically involves documentation of the characteristic gene rearrangement. This evidence concerns the gene EWSR1 and central nervous system neoplasm.