Carcinoid TumorMalignant Carcinoid SyndromeCarcinoid Heart DiseaseIleal NeoplasmsBronchial NeoplasmsAppendiceal NeoplasmsGastrointestinal NeoplasmsHydroxyindoleacetic AcidIntestinal NeoplasmsChromograninsOctreotideNeuroendocrine TumorsChromogranin AACTH Syndrome, EctopicDuodenal NeoplasmsLungThymus NeoplasmsLung NeoplasmsTumor Markers, BiologicalParaneoplastic Endocrine SyndromesProctoscopyCarcinoma, NeuroendocrineCommon Bile Duct NeoplasmsEnterochromaffin CellsLiver Neoplasms3-IodobenzylguanidineCell Line, TumorAmpulla of VaterReceptors, SomatostatinEndocrine Gland NeoplasmsSomatostatinIndium RadioisotopesJejunal NeoplasmsAppendixCushing SyndromeTumor BurdenTomography, X-Ray ComputedGastrinsTumor Necrosis Factor-alphaDuodenoscopyStomach NeoplasmsNeoplasm MetastasisImmunohistochemistryParaganglioma, Extra-AdrenalNeoplasms, Multiple PrimaryPolyps