VIP and carcinoid tumor: Both functioning NENs—such as glucagonomas [29,36,41], ACTH-secreting tumors [24,27], serotonin-secreting carcinoids [31,43], calcitonin-secreting neoplasms [39], and VIP- and/or dopamine-secreting tumors [23]—and non-functioning NENs have been implicated in thrombotic events.