Pheochromocytoma

A pheochromocytoma (from Greek phaios "dark", chroma "color", kytos "cell", -oma "tumor") or phaeochromocytoma (PCC) 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 birth, that secretes high amounts of catecholamines, mostly norepinephrine, plus epinephrine to a lesser extent. 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 and are named based upon the primary anatomical site of origin.