SarcomaBiopsySarcoma, EwingSarcoma, KaposiSarcoma, SynovialAvian Sarcoma VirusesBiopsy, NeedleSarcoma, ExperimentalSarcoma 180Sarcoma Viruses, MurineSoft Tissue NeoplasmsSarcoma, AvianHistiocytic SarcomaSarcoma, MyeloidSarcoma, Endometrial StromalSarcoma, Clear CellSarcoma, YoshidaKirsten murine sarcoma virusMoloney murine sarcoma virusSarcoma Viruses, FelineBone NeoplasmsRous sarcoma virusImage-Guided BiopsyBiopsy, Large-Core NeedleLeiomyosarcomaBiopsy, Fine-NeedleSarcoma, Alveolar Soft PartOsteosarcomaRNA-Binding Protein EWSHerpesvirus 8, HumanAlpharetrovirusCell Transformation, ViralProto-Oncogene Protein c-fli-1Harvey murine sarcoma virusRhabdomyosarcomaImmunohistochemistryGammaretrovirusHistiocytoma, Malignant FibrousLiposarcomaSentinel Lymph Node BiopsyCell Transformation, NeoplasticOncogene Proteins, FusionRetrospective StudiesSarcoma 37Histiocytoma, Benign FibrousMuscle NeoplasmsVascular NeoplasmsRetroperitoneal NeoplasmsSarcoma, Small CellLangerhans Cell SarcomaChick EmbryoPrognosisTreatment OutcomeIfosfamideTomography, X-Ray ComputedSkin NeoplasmsHemangiosarcomaFatal OutcomeDendritic Cell Sarcoma, FollicularHelper VirusesSensitivity and SpecificityBase SequenceAvian leukosis virusNeoplasm Recurrence, LocalNeuroectodermal Tumors, Primitive, PeripheralFibrosarcomaDNA, ViralRetroviridaeDoxorubicinTumor Markers, BiologicalExtremitiesTime FactorsMoloney murine leukemia virusCell LineAcquired Immunodeficiency SyndromeChondrosarcomaCombined Modality TherapyViral ProteinsGenes, ViralSkinFollow-Up StudiesPolymerase Chain ReactionNeoplasm StagingRNA-Binding Protein FUSRNA, ViralFibroblastsDendritic Cell Sarcoma, InterdigitatingAbdominal NeoplasmsNeoplasm TransplantationBronchoscopyLung NeoplasmsOncogenesPredictive Value of TestsHemangioendotheliomaRetroviridae ProteinsMethylcholanthreneProstatic NeoplasmsTranslocation, GeneticOncogenic VirusesNeuroectodermal Tumors