Pheochromocytoma (adrenaline-producing adrenal tumor)
What is pheochromocytoma?
A pheochromocytomaPheochromocytoma - a disease where too much adrenaline is being made by an adrenal tumor is a rare adrenaline-producing tumor that arises from the adrenal glands. Approximately 1,000 new cases are diagnosed each year in the United States (i.e. 2 to 8 cases per 1 million persons per year). Pheochromocytoma causes less than 0.2% of cases of hypertension (i.e. high blood pressure) each year.5,6
Figure 7: Pheochromocytoma
Pheochromocytomas grow within the center part of the adrenal gland termed the adrenal medulla. The adrenal medulla is part of the peripheral nervous system (i.e. the nerves outside the brain and spinal cord) and its main job is to make adrenalineAdrenaline - the hormone that helps control the "fight or flight" response and puts the body on "high alert" (also known as epinephrine), also known as epinephrine or catecholamine. Adrenaline is a hormoneHormone - a chemical made by a gland that travels in the bloodstream and "tells organs what to do." that affects such bodily functions as heart rate, blood pressure, breathing, digestion, sweating, urination, and sexual arousal. Adrenaline is said to control the "fight or flight" response, or in other words, it gets your body ready to react to stressful situations. Adrenaline is normally released from the adrenal medulla when there is danger or in an emergency situation. In addition to raising heart rate and blood pressure, adrenaline opens air passages to allow in more oxygen, and boosts the supply of oxygen and glucoseGlucose - sugar used by the body as energy (sugar) to the brain and muscle. Pheochromocytomas secrete adrenaline in an uncontrolled fashion and can cause serious health problems including stroke, heart attack, and even death. Some physicians call pheochromocytoma a "pharmacological time bomb" because of its danger.
Adrenaline-producing tumors that grow outside of the adrenal glands are called "paragangliomas" and are discussed in more detail in that section. (See Paraganglioma) Approximately 95% of adrenaline-secreting tumors are located within the abdomen, and of these, 85 to 90% are in the adrenal glands. Approximately 10% of pheochromocytomas are bilateral (i.e. in both adrenal glands).
Pheochromocytoma is sometimes called the "10% tumor" because approximately 10% are bilateral (i.e. in both adrenal glands), 10% are found in children, 10% are genetic (i.e. inherited), 10% are cancer, and 10% are found outside the adrenal gland (i.e. paragangliomaParaganglioma - a disease where too much adrenaline is being made by a tumor outside the adrenal glands). As we learn more about this uncommon disease, we are finding that these percentages are not necessarily accurate. For example, it is thought that up to 25% of pheochromocytomas are inherited.
Anyone can develop a pheochromocytoma, from the very young to the elderly. Most arise spontaneously (i.e. are not genetic). There are no known risk factors except in genetic (i.e. inherited or familial) cases.