Gastrointestinal Stromal TumorsProto-Oncogene Proteins c-kitGastrointestinal NeoplasmsBenzamidesPiperazinesPyrimidinesReceptor, Platelet-Derived Growth Factor alphaStromal CellsAntineoplastic AgentsMesenchymomaNeoplasms, Connective TissueEpithelioid CellsMitotic IndexDuodenal NeoplasmsPyrrolesLeiomyosarcomaImmunohistochemistryIleal NeoplasmsJejunal NeoplasmsNeoplasms, Multiple PrimaryMutationIntestinal NeoplasmsTumor Markers, BiologicalIndolesStomach NeoplasmsProtein Kinase InhibitorsSex Cord-Gonadal Stromal TumorsTomography, X-Ray ComputedDigestive System Surgical ProceduresDNA Mutational AnalysisNeurofibromatosis 1SarcomaPrognosisCarney ComplexLeiomyomaGastrectomyTreatment OutcomeAntigens, CD34Drug Resistance, NeoplasmInterstitial Cells of CajalEndosonographyExonsDisease-Free SurvivalLaparotomyNeurilemmomaTumor BurdenSomatostatinomaProtein-Tyrosine KinasesCell Line, TumorS100 ProteinsRetrospective StudiesLeiomyoma, EpithelioidGastroscopyElectron Transport Complex IIPositron-Emission TomographyDisease ProgressionPeritoneal NeoplasmsEndoscopy, GastrointestinalPelvic NeoplasmsSuccinate DehydrogenaseDouble-Balloon EnteroscopyOmentumIncidental FindingsKi-67 AntigenSoft Tissue NeoplasmsNeoplasm MetastasisNeurofibrosarcomaGastrointestinal HemorrhageIntestine, SmallDNA, NeoplasmNeoadjuvant TherapyCell ProliferationGene Expression Regulation, NeoplasticHemoperitoneumBiopsy, NeedleLiver NeoplasmsLethargyNeoplasm ProteinsNeoplasm Recurrence, LocalSurvival RateMeckel DiverticulumFollow-Up StudiesEndometrial Stromal TumorsNeoplasm StagingKaplan-Meier Estimate