Neuroendocrine tumors represent the most frequent tumor of the small intestine. These serotonin-producing tumors arise from enterochromaffin cells of the distal small intestine, appendix, and proximal colon. They are often slow growing, which contributes to the insidious onset of symptoms. When clinically recognized, afflicted patients often present with advanced disease and a poor 5-year prognosis (∼36%).