<prompt> All of the following are associated with pheochromocytoma except: March 2010Ventricular arrhythmiasInterstitial fibrosisHypotensionEctopic ACTH production  <response>: Ans. C: Hypotension Pheochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands originating in the chromaffin cells, or extra-adrenal chromaffin tissue that failed to involute after bih and secretes excessive amounts of catecholamines, usually adrenaline epinephrine if in the adrenal gland and not extra-adrenal, and noradrenaline norepinephrine. Extra-adrenal paragangliomas often described as extra-adrenal pheochromocytomas are closely related, though less common, tumors that originate in the ganglia of the sympathetic nervous system. Because of excessive catecholamine secretion, pheochromocytomas may precipitate life-threatening hypeension or cardiac arrhythmias. Nonspecific myocardial changes includes focal necrosis, mononuclear infiltrates and interstitial fibrosis. In some cases pheochromocytoma secrete other hormones, such as ACTH and somatostatin. 