MediastinumLymphatic DiseasesMediastinal NeoplasmsImmunoblastic LymphadenopathyMediastinal DiseasesTuberculosis, Lymph NodeMediastinal CystMediastinoscopyHistiocytosis, SinusLymph NodesLymphadenitisTomography, X-Ray ComputedHistiocytic Necrotizing LymphadenitisRadiography, ThoracicNeckAIDS-Related ComplexThoracotomyMediastinitisSplenomegalyGiant Lymph Node HyperplasiaGoiter, SubsternalThymus NeoplasmsBiopsy, Fine-NeedleHomosexualityBiopsy, NeedleThoracic Surgery, Video-AssistedCat-Scratch DiseaseThoracic Surgical ProceduresPleural CavityBiopsyThoracic NeoplasmsSarcoidosisThymomaBronchoscopyEndosonographyBronchogenic CystHistiocytesThoracoscopyPneumomediastinum, DiagnosticHepatomegaly3-IodobenzylguanidineMediastinoscopesFatal OutcomeHypergammaglobulinemiaBartonella henselaeLymphoproliferative DisordersLymphangioma, CysticThoracic DiseasesChoristomaLymphomaSternumSuperior Vena Cava SyndromeEsophageal CystVisible Human ProjectsSarcoidosis, PulmonaryAcquired Immunodeficiency SyndromeAngiolymphoid Hyperplasia with EosinophiliaDeltaretrovirusGallium RadioisotopesHodgkin DiseasePleural EffusionAutoimmune Lymphoproliferative SyndromeRetrospective StudiesLymphatic MetastasisTreatment OutcomeIncidental FindingsMice, Inbred MRL lprLung NeoplasmsEsophageal PerforationGanglioneuromaGastroscopesPseudolymphomaPrednisolonePlasma Cell Granuloma, PulmonaryRadiopharmaceuticalsParathyroid NeoplasmsNeurilemmomaMediastinal EmphysemaThymus HyperplasiaLiposarcomaSeminomaRetroperitoneal NeoplasmsToxoplasmosisLymphangiomaLymphoma, T-CellChylothoraxImmunohistochemistryPleuraPositron-Emission TomographyThoracostomyThymectomyLymphoma, Non-HodgkinHematemesisSyndromeEndoscopic Ultrasound-Guided Fine Needle AspirationFollow-Up StudiesMagnetic Resonance ImagingSkin DiseasesSpermatoceleAngiomatosis, Bacillary