Pheochromocytomas arise from:

Answer is D (Neuroendocrine cells of the adrenal medulla): Pheochromocytomas are catecholamine secreting tumors that arise from neuroendocrine chromaffin tissue in the adrenal medulla. The adrenal medulla consists of neuroendocrine cells called chromaffin cells Chromaffin cells are derived from primitive pheochromblasts of the developing sympathetic nervous system. Chromaffin cells are the site of catecholamine biosynthesis Pheochromocytomas arise from chromaffin cells in the adrenal medulla Most pheochromocytomas secrete both norepinephrine and epinephrine The percentage of norepinephrine is usually greater than epinephrine (Often as high as 20:1) Most Extra-adrenal pheochromocytomas (paragangliomas) secrete norepinephrine exclusively