Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Pheochromocytomas are a type of tumor of the adrenal glands that can release high levels of epinephrine and norepinephrine. As the name implies, the adrenalglands are located near the "renal" (kidney) area. One adrenal gland sits on top of each of the two kidneys.
Despite their small size, the adrenal glands have many functions. They are complex endocrine (hormone secreting) glands. Cells in different regions of the adrenal glands have different functions in the endocrine system.The outer portion of the adrenal gland is called the adrenal cortex. In part of the adrenal cortex (zona fasciculata and zona reticularis) the cells secrete cortisol, a hormone similar to cortisone, which is essential for handling stresses In another area (zona glomerulosa) cells secrete a hormone called aldosterone which helps in water and salt regulation and blood pressure control.
The inner area of the adrenal gland is referred to as the adrenal medulla. This is where the cells secrete substances called catecholamines -- epinephrine, norepinephrine and dopamine. These are "flight or fight" hormones. They are responsible in part for that feeling of an "adrenaline" rush people feel when they are afraid. It is these cells that are overproduced by a pheochromocytoma. Basically, a pheochromocytoma is a tumor of these catecholamine-secreting cells, and that causes the clinical signs and symptoms we will discuss below. The catecholamine-secreting cells are sometimes referred to as chromaffin cells, and they are found in other areas of the body as well as in the adrenal medulla.
Sometimes, pheochromocytomas arise from chromaffin cells that are located outside of the adrenal gland. In this case, they are termed extra-adrenal pheochromocytomas or paragangliomas and are usually located in the abdomen.
Pheochromocytomas may occur in persons of any age. The peak incidence is between the third and the fifth decades of life. Pheochromocytomas are, fortunately, quite rare, and most of them are benign.
Someone with a pheochromocytoma usually has three classic symptoms, headache,
sweating, and heart palpitations (a fast heart beat) in association with
markedly elevated blood pressure (hypertension). Other conditions that may
accompany these classic symptoms are as follows:
abdominal pain, and
Some people, however, never develop symptoms of a pheochromocytoma. Up to 10%
of cases are discovered incidentally, meaning that they are not suspected and
only found when the patient is undergoing diagnostic studies for other