Glioblastoma (GBM) is the most common adult primary intracranial neoplasm ... as glioblastoma multiforme; the multiforme refers to the tumor heterogeneity.×ArticlesLogInCasesSignUpCoursesQuizBlogDonateAbout×MenuSearchADVERTISEMENT:Radiopaediaisfreethankstooursupportersandadvertisers.BecomeaGoldSupporterandseenoads.ArticlesCasesCoursesLogInLoginSignup{"url":"/signup-modal-props.json?lang=us\u0026email="}ArticlesCasesCoursesQuizAboutBlogGoad-freeSearchGlioblastomaDrDaliaIbrahim◉andAssocProfFrankGaillard◉◈etal.Glioblastoma(GBM) isthemostcommonadultprimaryintracranialneoplasm(seebraintumors),accountingfor15%ofallintracranialneoplasmsandapproximately50%ofallastrocytomas.GBMsarehigh-gradeastrocytomas;theyarethereforegenerallyaggressive,largelyresistanttotherapy,andhaveacorrespondingpoorprognosis.Theyhaveapredilectionforspreadingalongthecondensedwhitemattertractssuchascorticospinaltractsandcorpuscallosumtoinvolvethecontralateralhemisphere.Onthispage:Article:TerminologyPrimaryvssecondaryVariantsEpidemiologyClinicalpresentationPathologyRadiographicfeaturesRadiologyreportTreatmentandprognosisHistoryandetymologyDifferentialdiagnosisRelatedarticlesReferencesImages:CasesandfiguresImagingdifferentialdiagnosisTerminologyGlioblastomawaspreviouslyknownasglioblastomamultiforme;themultiformereferstothetumorheterogeneity. TheWHOclassification hasdroppedthe'multiforme'andthusitisbesttorefertothesetumorsmerelyasglioblastomas.SomewhatconfusinglytheabbreviationGBMisstillconsideredappropriate16.PrimaryvssecondaryGlioblastomashavetraditionallybeendividedintoprimaryandsecondary;theformerarisingdenovo(90%)whereasthelatterdevelopedfromapre-existinglowergradetumor(10%). ThesecorrelatecloselytoIDHmutationstatus: IDHmutant:generallysecondaryglioblastoma,almostalwaysMGMT methylated17IDHwild-type:generallyprimaryglioblastomaIfIDHstatusisunavailableorindeterminatethencurrentlythediagnosisofglioblastomaNOS (nototherwisespecified)shouldbemade16. PrimaryPrimaryglioblastomasarethosethatarisedenovo,withou