This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine, Subject name: Pathology
[{'content': 'Most common site for pheochromocytoma is? \nSelect and explain. \nA. Adrenal medulla, B. Adrenal cortex, C. Paravertebral ganglion, D. Paraaortic-sympathetic chain', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Adrenal medulla * Pheochromacytomas arise in adrenal medulla (not in adrenal cortex) and at extra-adrenal sites along sympathetic chain.* Most pheochromocytomas arise in adrenal medulla* Pheochromocytomas are catecholamine secreting tumors arising from chromaffin cells.* About 10% of these tumors arise at extra-adrenal sites, where they are called paragangliomas. These extra- adrenal sites area) Along the para-aortic sympathetic chain.b) Organ of Zuckerkandl (paravertebral ganglion).c) Along the sympathetic chain in neck and mediastinum.d) In the wall of urinary bladder.", 'role': 'assistant'}]