The role of gamma knife radiosurgery in occurrence of secondary gliosarcoma after treatment of glioblastoma: A case report

•Secondary gliosarcoma following gamma knife radiosurgery for glioblastoma was rarely reported.•The transformation from glioblastoma to gliosarcoma could be further facilitated by radiation.•Specific genetic features could facilitate the transformation when radiation is applied.•To find which genetic subtype is more vulnerable to radiation, additional study will be needed.