Pheochromocytomas and Paragangliomas
What are Pheochromocytomas and Paragangliomas?
Pheochromocytomas, often known as ‘pheos’ (‘fee-ohs’), are rare, usually noncancerous (benign), slow-growing tumors which occur in the inner part of the adrenal gland. Rarely, they can occur elsewhere in the body, when they are usually called paragangliomas or ‘paras’.
The body has two adrenal glands, one on top of each kidney (‘adrenal’ means ‘next to the kidney’). Even though the glands are as small as a walnut, they are important as they make a number of important hormones (chemical messengers). Pheos grow in the middle part of the adrenal gland which is called the medulla. The adrenal medulla makes hormones called catecholamines such as adrenaline and noradrenaline. These hormones help the body to keep blood pressure at the right level and to deal with sudden stress or threats. Pheos may make more of these hormones than normal, causing a wide range of symptoms that can affect the whole body.
Paraganglioma are rare, usually noncancerous (benign), slow-growing tumors that are closely related to pheochromocytoma. Paras originate from outside the adrenal glands, specifically from the parasympathetic or sympathetic nervous system. Just like pheos, paras are also characterized by the presence of an excess amount of hormones called catecholamines, which lead to persistent or episodic high blood pressure and other symptoms. Although it is rare, some paras do not produce excess catecholamines, so common symptoms such as high-blood pressure, sweating or heart palpitations do not appear. These non-secreting paragangliomas are often found incidentally.
- Pheos are rare and occur in only around 1 per 100 000 people per year
- Most pheos (around 8 out of 10 or 80%) are benign tumors (i.e. not cancer)
- More than 8 in 10 or 80% of pheos grow in the adrenal glands
- Approximately 35% of pheos and paras are hereditary. All patients diagnosed should consult with their doctor to determine if genetic testing is appropriate
- Pheos diagnosed in children are more likely to be related to a condition that runs in families than those that occur in adults
- The most common age for diagnosis is between 30-60 years of age, although 1 in 10 or 10% are found in children
- Pheos occur equally in all genders and races
- If detected early, pheochromocytoma and paraganglioma can be successfully removed with surgery in the vast majority of cases.
What are the Symptoms of Pheochromocytoma and Paraganglioma?
Pheos can cause a wide range of symptoms. These are mainly due to the release of larger than normal amounts of hormones by the tumor. Symptoms can occur from time to time, often in episodes lasting only 15 minutes and may include some or all of the following:
- Sudden headaches
- Feeling dizzy
- Looking pale
- Sweating more than normal
- Fast or uneven heart rate (palpitations)
- Panic attacks / sense of doom
- Weight loss
- Heat intolerance
- High (and rarely low) blood pressure (all the time or in short episodes)
- Feeling sick (with or without being sick)
- Changes in blood sugar levels
Many of the symptoms listed above are related to the high blood pressure (hypertension) that can be caused by the tumor. It is thought that one case of hypertension in every 500-1000 patients is due to pheochromocytoma. Hypertension in patients with undiagnosed pheos can be very difficult to control; however, once a diagnosis is made, special drugs are available to help to control it. Some paras do not produce any catecholamines, so common symptoms mentioned above do not appear.
If pheochromocytoma or paraganglioma is suspected a diagnosis can be made using the twenty-four hour urine or blood (plasma) test. With both tests, catecholamines and metanephrines (which are metabolites of catecholamines) are measured. Many patients have symptoms for years before a diagnosis. If a pheo or para is suspected, you should see an endocrinologist (a doctor who specializes in hormonal disorders.
Sometimes pheos and paras may be found before they have the chance to cause symptoms. This may happen when a person is having a scan for another reason. It may also occur because they have a condition or genetic mutation which indicates a higher risk of developing a pheo or para, so they are scanned regularly to look for the tumors.