CD99 is a transmembrane protein with various functions and limited diagnostic utility in the differential diagnosis of small round blue cell ...AuthorsBlogBoardReviewCommentContactUsNewslettersStatisticsTestimonialsSeeElsevier'snewvideoabouttheirClinicReviewArticlesonourhomepageorclickhere.JobsFellowshipsConferences/WebinarsBooksCMECasesAdvertiseGrantsMedicalNewsLibrariesRocheCompanionDiagnosticLibraryRocheNTRKIHCDiagnosticLibraryCOVID-19LibraryPandemicreliefmusicawardHome>CDmarkers>CD99CDMarkersCD99Authors: FridoBruehl,M.D.,ChristianM.Schürch,M.D.,Ph.D.EditorialBoardMembers: ElizabethCourville,M.D.,BorislavA.Alexiev,M.D.DeputyEditor-in-Chief: GenevieveM.Crane,M.D.,Ph.D.TopicCompleted:1April2021Minorchanges:1April2021Copyright:2002-2021,PathologyOutlines.com,Inc.PubMedSearch:CD99[TI]Pageviewsin2020:23,153Pageviewsin2021todate:7,799TableofContentsDefinition/general|Essentialfeatures|Terminology|Pathophysiology|Diagrams/tables|Clinicalfeatures|Interpretation|Usesbypathologists|Prognosticfactors|Microscopic(histologic)description|Microscopic(histologic)images|Positivestaining-normal|Positivestaining-disease|Negativestaining|Additionalreferences|Boardreviewstylequestion#1|Boardreviewstyleanswer#1Citethispage:BruehlF,SchürchCM.CD99.PathologyOutlines.comwebsite.https://www.pathologyoutlines.com/topic/cdmarkerscd99.html.AccessedApril13th,2021.Definition/generalTransmembraneproteinwithvariousfunctionsandlimiteddiagnosticutilityInthedifferentialdiagnosisofsmallroundbluecelltumorsEssentialfeaturesExistsin2isoformsandhasvariableoncogenicandtumorsuppressorfunctionsPositivityforCD99isnotspecificbutitsabsencerulesoutEwingsarcomaintheworkupofasmallblueroundcelltumorDot-likestainingpatternhasbeenreportedinseveraldiseaseentitiesbuthassofarnotbeenproventobediagnosticallyusefulTerminologyAlsocalledMIC2,TcellsurfaceglycoproteinE2,p30/32protein(HumMolGenet1993;2:417)PathophysiologyGeneislocatedinthepseudoautosomalregionofchromosomeX(PhilosTransRSocLondBBiolSci1988;322:145)2distinctprote