Retroperitoneal NeoplasmsRetroperitoneal SpaceRetroperitoneal FibrosisLiposarcomaTesticular NeoplasmsNeoplasms, Germ Cell and EmbryonalTomography, X-Ray ComputedPancreatic NeoplasmsLymph Node ExcisionGanglioneuromaSarcomaLaparoscopyNeurilemmomaCystadenoma, MucinousUreteral ObstructionAbdominal NeoplasmsKidney NeoplasmsNeoplasmsLaparotomyLeiomyosarcomaGerminomaHematomaCystadenocarcinoma, MucinousTeratomaNeoplasms, Cystic, Mucinous, and SerousTreatment OutcomeAbdominal AbscessOrgan Sparing TreatmentsNeoplasms, Multiple PrimaryVena Cava, InferiorSeminomaDuodenal ObstructionNephrectomyRetrospective StudiesVascular NeoplasmsNeoplasm Recurrence, LocalAortic Aneurysm, AbdominalIliac ArteryAdrenal Gland NeoplasmsSoft Tissue NeoplasmsHerniaPelvic NeoplasmsSkin NeoplasmsAbdomenHydronephrosisNeoplasm StagingChylous AscitesLymphoceleHemoperitoneumRadiography, AbdominalPancreaticoduodenectomyLipomaFatal OutcomeParaganglioma, Extra-AdrenalFollow-Up StudiesUreterUrologic Surgical ProceduresNeoplasms, Second PrimaryImmunohistochemistryParagangliomaLiver Neoplasms