A pheochromocytoma (fee-o-kroe-moe-sy-TOE-muh) is a rare, usually noncancerous (benign) tumor that develops in an adrenal gland. You have two adrenal glands — one located at the top of each kidney. The adrenal glands are part of the body's hormone-producing (endocrine) system. The endocrine system also includes the pituitary gland, thyroid gland, parathyroid glands, pancreas, ovaries (in females) and testicles (in males).

Usually, a pheochromocytoma develops in only one adrenal gland. But tumors can develop in both.

If you have a pheochromocytoma, the tumor releases hormones that may cause high blood pressure, headache, sweating and symptoms of a panic attack. If a pheochromocytoma isn't treated, severe or life-threatening damage to other body systems can result.

Surgery to remove a pheochromocytoma usually returns blood pressure to normal.


Signs and symptoms of pheochromocytomas often include:

  • High blood pressure
  • Headache
  • Heavy sweating
  • Rapid heartbeat
  • Tremors
  • Pallor
  • Shortness of breath
  • Panic attack-type symptoms

Less common signs or symptoms may include:

  • Anxiety or sense of doom
  • Blurry vision
  • Constipation
  • Weight loss

Symptomatic spells

The symptoms of pheochromocytoma may be constant, or they may occur, or get stronger, occasionally. These spells can happen because of activities or conditions, foods high in a substance that affects blood pressure (tyramine), and medications.

Certain activities or conditions can make symptoms worse, such as:

  • Physical hard work
  • Anxiety or stress
  • Changes in body position, such as going from sitting or lying down to standing
  • Labor and delivery
  • Surgery and a drug that causes you to be in a sleep-like state during surgery (anesthesia)

Foods high in tyramine, a substance that affects blood pressure, also can make symptoms worse. Tyramine is common in foods that are fermented, aged, pickled, cured, overripe or spoiled. These foods include:

  • Some cheeses
  • Some beers and wines
  • Chocolate
  • Dried or smoked meats

Certain medications that can make symptoms worse include:

  • Monoamine oxidase inhibitors (MAOIs), such as phenelzine (Nardil), tranylcypromine (Parnate) and isocarboxazid (Marplan)
  • Stimulants, such as amphetamines or cocaine

When to see a doctor

Although high blood pressure is a primary sign of a pheochromocytoma, most people who have high blood pressure don't have an adrenal tumor. Talk to your health care provider if any of these factors apply to you:

  • Difficulty controlling high blood pressure with current treatment
  • Spells of worsening high blood pressure
  • A family history of pheochromocytoma
  • A family history of a related genetic disorder: multiple endocrine neoplasia, type 2 (MEN 2), von Hippel-Lindau disease, hereditary paraganglioma syndromes or neurofibromatosis 1


Researchers don't know exactly what causes a pheochromocytoma. The tumor develops in specialized cells, called chromaffin cells, located in the center of an adrenal gland. These cells release certain hormones, primarily adrenaline (epinephrine) and noradrenaline (norepinephrine). These hormones help control many body functions, such as heart rate, blood pressure and blood sugar.

Adrenaline and noradrenaline trigger the body's fight-or-flight response to a perceived threat. The hormones cause blood pressure to increase and the heart to beat faster. They prepare other body systems that enable you to react quickly. A pheochromocytoma causes more of these hormones to be released, and it causes them to be released when you're not in a threatening situation.

Most of the chromaffin cells are in the adrenal glands. But small clusters of these cells are also in the heart, head, neck, bladder, back wall of the stomach (abdomen) and along the spine. Chromaffin cell tumors located outside of the adrenal glands are called paragangliomas. They may cause the same effects on the body as a pheochromocytoma.

Risk factors

Most pheochromocytomas are discovered in people between the ages of 20 and 50. But the tumor can develop at any age.

People who have certain rare inherited disorders have an increased risk of pheochromocytoma or paraganglioma. Tumors associated with these disorders are more likely to be cancerous. Tumors are also more likely to occur in both adrenal glands. These genetic conditions include:

  • Multiple endocrine neoplasia, type 2 (MEN 2) is a disorder that results in tumors in more than one part of the endocrine system. There are two types of MEN, type 2A and type 2B, that both involve pheochromocytomas. Other tumors associated with this condition can appear on other parts of the body, including the thyroid, parathyroid, lips, tongue and digestive system.
  • Von Hippel-Lindau disease can cause tumors at many sites, including the central nervous system, endocrine system, pancreas and kidneys.
  • Neurofibromatosis 1 causes many tumors in the skin (neurofibromas), pigmented skin spots and tumors of the optic nerve.
  • Hereditary paraganglioma syndromes are inherited disorders that result in either pheochromocytomas or paragangliomas.


High blood pressure can damage organs, particularly tissues of the heart and blood vessel (cardiovascular) system, brain and kidneys. This damage can cause several critical conditions, including:

  • Heart disease
  • Stroke
  • Kidney failure
  • Problems with the nerves of the eye

Cancerous tumors

Rarely, a pheochromocytoma is cancerous, and the cancerous cells spread to other parts of the body. Cancerous cells from a pheochromocytoma or paraganglioma most often travel to the lymph system, bones, liver or lungs.

May 21, 2022

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