This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
[{'content': 'Most common site for carcinoid tumor in the abdomen \nSelect and explain. \nA. Appendix, B. Liver, C. Intestines, D. Pancreas', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .CARCINOID TUMOUR It commonly occurs in appendix (65%), ileum (25%), other pas of GIT and rarely bronchus, testis, ovary. In the small intestine, carcinoids are most often seen within the terminal 2 feet of the ileum. * They arise from the enterochromaffin cells (Kulchitsky cells) found in the crypts of Lieberkuhn. * These cells are capable of APUD (Amine precursor uptake and Decarboxylation) and can secrete vasoactive peptides. * Carcinoid syndrome is seen in 40% of patients. * Carcinoid in appendix is usually single. But commonly it causes luminal obstruction and so presents with features of appendicitis. Common site is at tip/distal 2/3. ref:SRB&;s manual of surgery ,ed 3,pg no 812', 'role': 'assistant'}]