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 “ad-renal” glands are located near
the "renal" (kidney) area. In other words, the adrenal glands are small glands that are
located near the top of the kidneys. 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. There is an
area (zona fasciculata) where the cells secrete cortisol, a hormone similar to
cortisone. There is another area (zona glomerulosa) where cells secrete a
hormone called aldosterone
which helps in water regulation.
There is yet another area, referred to as the adrenal medulla, 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
involved in 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 (2
to 8 people per million per year), and the majority of them are entirely 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
The parathyroid glands are four, small, pea-shaped glands that are located in the neck on either side of the trachea (the main airway) and next to the thyroid gland. In most cases there are two glands on"...