Cystadenocarcinoma, MucinousAdenocarcinoma, MucinousAdenocarcinomaAppendiceal NeoplasmsCarcinoma, Signet Ring CellCystadenoma, MucinousPseudomyxoma PeritoneiCystadenomaCystadenoma, PapillaryPancreatic CystCystadenoma, SerousRectal FistulaCystadenocarcinomaCecal NeoplasmsUrachal CystCalymmatobacteriumPerineumPancreatic NeoplasmsImmunohistochemistryNeoplasms, Cystic, Mucinous, and SerousCystsMucin-2Tumor Markers, BiologicalOvarian NeoplasmsAdenocarcinoma, PapillaryPancreatic PseudocystMucinsStomach NeoplasmsColorectal NeoplasmsNeoplasm StagingNeoplasms, Complex and MixedTomography, X-Ray ComputedColonic NeoplasmsNeuroendocrine TumorsCystadenocarcinoma, PapillaryLymphangioma, CysticMucoceleCell Line, TumorLung NeoplasmsPancreatectomyIndium RadioisotopesRectal NeoplasmsPrognosisMicrosatellite InstabilityPositron-Emission Tomography