what is pheochromocytoma
What is a pheochromocytoma. Pheochromocytoma is a part of the pheochromocytoma and paraganglioma group of syndromes. A pheochromocytoma is a tumor arising in the adrenal gland medulla.A paraganglioma grows in the sympathetic or parasympathetic nerves. pheochromocytoma is a functional catecholamine-secreting tumor of the adrenal gland medulla. Catecholamines include epinephrine, norepinephrine and their derivatives. In normal amounts these hormones are responsible for regulating heart rate and blood pressure, among other functions.