Gastrointestinal Stromal TumorsCarcinoid TumorGastrointestinal NeoplasmsProto-Oncogene Proteins c-kitBenzamidesPiperazinesPyrimidinesReceptor, Platelet-Derived Growth Factor alphaMalignant Carcinoid SyndromeIleal NeoplasmsStromal CellsCarcinoid Heart DiseaseDuodenal NeoplasmsIntestinal NeoplasmsAntineoplastic AgentsMesenchymomaImmunohistochemistryTumor Markers, BiologicalNeoplasms, Connective TissueJejunal NeoplasmsMitotic IndexEpithelioid CellsPyrrolesNeoplasms, Multiple PrimaryLeiomyosarcomaBronchial NeoplasmsAppendiceal NeoplasmsStomach NeoplasmsTomography, X-Ray ComputedMutationSex Cord-Gonadal Stromal TumorsIndolesProtein Kinase InhibitorsDNA Mutational AnalysisDigestive System Surgical ProceduresTreatment OutcomePrognosisNeuroendocrine TumorsTumor BurdenNeurofibromatosis 1Cell Line, TumorHydroxyindoleacetic AcidGastrectomySarcomaChromograninsOctreotideCarney ComplexAntigens, CD34LeiomyomaLiver NeoplasmsRetrospective StudiesChromogranin ADisease-Free SurvivalNeoplasm MetastasisDrug Resistance, NeoplasmAmpulla of VaterInterstitial Cells of CajalLaparotomyExonsEndosonographyNeurilemmomaGastroscopyPositron-Emission TomographySomatostatinomaMeckel DiverticulumDisease ProgressionACTH Syndrome, EctopicCell ProliferationKi-67 AntigenS100 ProteinsDNA, NeoplasmProtein-Tyrosine KinasesLeiomyoma, EpithelioidTumor Necrosis Factor-alphaIntestine, SmallPeritoneal NeoplasmsNeoplasm Recurrence, LocalAdenocarcinomaBiopsy, NeedleNeoplasm StagingSurvival RateEndoscopy, GastrointestinalThymus NeoplasmsNeoplasm ProteinsSoft Tissue NeoplasmsPancreaticoduodenectomyFollow-Up StudiesGene Expression Regulation, NeoplasticElectron Transport Complex IIPancreatic NeoplasmsIncidental FindingsDouble-Balloon EnteroscopySurvival AnalysisAbdominal NeoplasmsOmentumNeurofibrosarcomaPelvic NeoplasmsBiopsyNeoadjuvant TherapyImmunoenzyme Techniques