Pheochromocytoma, or “pheo,” is a rare tumor that develops in the adrenal glands. It affects the production of adrenalin and can result in high blood pressure and other health concerns. It is usually benign.
Most benign cases involve only one adrenal gland, but the condition can affect both. The adrenal glands are two small endocrine glands that sit above the kidneys. They help create and distribute important hormones, including adrenaline and cortisol.
Adrenal hormones help balance functions such as:
As a result, pheochromocytoma can affect a wide range of bodily functions.
In pheochromocytoma, the adrenal glands produce too much adrenaline, noradrenaline, or both.
These hormones help balance heart rate, blood pressure, and stress response, including the fight-or-flight response.
When levels of these hormones are too high, the body can enter a state resembling chronically high stress. The body will react as though it is constantly under stress.
Pheochromocytomas are related to another type of tumor called paragangliomas. These grow in the same types of tissue but on the outside of the adrenal glands. Both can result in abnormalities of the adrenal hormones.
Some people experience consistent high blood pressure, while others may experience episodes of high blood pressure. These may occur from several times per day to twice per month.
Other symptoms usually occur in episodes, with a distinct combination.
The most common symptoms of pheochromocytoma are:
- heart palpitations
Other symptoms that can occur during an episode or independently include:
- stomach pain
- weight loss
- rapid heart rate
- anxiety or a sense of doom
- feeling shaky
- being extremely pale
- mood swings and irritability
- high blood sugar
Symptoms may last for seconds or hours. They tend to worsen over time and become more frequent as the tumor grows.
However, some people experience no symptoms. These people may only discover that they have pheochromocytoma when they undergo an imaging test for another condition.
Pheochromocytoma can disturb the normal functioning of the adrenal glands. This can increase the risk of an adrenergic crisis, which occurs when bursts of adrenal hormones enter the bloodstream.
Symptoms of an adrenergic crisis include extremely high blood pressure and a rapid heart rate.
Having these symptoms does not mean a person definitely has pheochromocytoma, as they can occur with other conditions. However, anyone who notices these symptoms should see a doctor for diagnosis.
What causes hypertension? Find out more here.
Doctors do not know exactly what causes pheochromocytoma. Many appear randomly, but genetic factors appear to play a role in some cases.
In around 25–35% of cases, a person inherits the condition, according to the National Organization for Rare Diseases.
It is most likely to appear at the age of 20–50 years, but it can appear at any age.
A person with genetic features linked to pheochromocytoma may also have a higher risk of developing a range of other conditions, including:
- von Hippel–Lindau syndrome
- multiple endocrine neoplasia type 2
- neurofibromatosis type 1
- Sturge–Weber syndrome
For this reason, a person with a diagnosis of pheochromocytoma should consider undergoing genetic testing to assess for a risk of other complications.
Episodes can occur at any time, but certain life events can also trigger them.
Possible triggers include:
- straining the body during hard physical activity or childbirth
- undergoing a surgery or procedure that involves anesthesia
- high levels of emotional or physical stress
A compound called tyramine may also trigger symptoms. Tyramine is present in fermented or aged foods, such as red wine, chocolate, and some cheeses.
In some people, certain drugs may also trigger symptoms. For example, monoamine oxidase inhibitors — a treatment option for depression and other mental health conditions — have been known to trigger symptoms.
Diagnosing pheochromocytoma can be difficult, as it is rare and affects different people in different ways.
A person with any of the following should undergo testing to rule out or confirm pheochromocytoma:
- episodes of high blood pressure or constant high blood pressure
- heart palpitations, sweating, headaches, or other symptoms
- an incidental adrenal mass
A number of tests can help check for key markers of the condition. For example:
Blood or urine tests: These can show if a person has unsually high levels of adrenaline or noradrenaline in their body.
Imaging tests: A CT or MRI scan of the adrenal glands may confirm the presence of a tumor. Pheochromocytomas often have a characteristic appearance on imaging tests.
Genetic testing: If investigations confirm a tumor, a doctor may recommend genetic testing. This can show if the person has a gene mutation that increases the risk of this and other tumors. If a gene mutation is present, they may also recommend screening for family members.
A doctor will usually recommend removing the tumor surgically. Surgeons often opt for laparoscopic surgery, which involves only small incisions.
Pheochromocytoma usually affects only one adrenal gland. A surgeon may therefore remove the entire gland, as the remaining gland can produce enough hormones for the body to survive.
If tumors occur in both glands, the surgeon will try to remove the tumor tissue only, leaving a part of the glands intact. If this is not possible, they may have to remove both adrenal glands.
If the surgeon removes both adrenal glands, the body will no longer be able to produce adrenal hormones. The person will need to take steroids to help replace these hormones.
During surgery, changes in blood pressure or an irregular heartbeat can lead to complications. For some days before the surgery, the person may need to take medication to balance out their heart rate and lower their blood pressure.
Most pheochromocytomas are benign. After surgery, the symptoms will usually go away.
In some cases, however, the person will have a malignant tumor that can recur at distant sites, usually the lung, bones, or liver.
If the tumor is malignant, treatment options include:
Addison’s disease also affects the adrenal glands. Learn more here.
Most pheochromocytomas are benign. However, without treatment, they can lead to complications.
Possible complications include:
- heart muscle disease (cardiomyopathy)
- a heart attack (myocardial infarction)
- bleeding in the brain (cerebral hemorrhage)
- a buildup of fluid in the lungs (pulmonary edema)
A person may also have high blood pressure that is difficult to control.