PHF5A and atypical teratoid rhabdoid tumor: Identified in the late 1990s as a separate entity from MB and more broadly from the formally named PNET, atypical teratoid rhabdoid tumor (ATRT) is a subset of aggressive CNS embryonal tumors of early childhood characterized by the loss of expression of INI by immunohistochemistry (IHC), which were, until recently, associated with a very dismal prognosis [68,69].