What are Pheochromocytomas?

Photo capture: adrenal glands

Pheochromocytomas (pheochromocytomas), often known as ‘pheos’ (‘fee-ohs’), are rare 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.

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.

Pheos can affect people of all ages, including children. Because they make hormones, pheos are classed as a special type of tumor called a neuroendocrine tumor (NET)

  • 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
  • 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

Pheos diagnosed in children are more likely to be related to a condition that runs in families than those that occur in adults.

What are the Symptoms of Pheochromocytomas?

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
  • Anxiety
  • Weight loss
  • Heat intolerance
  • High (and rarely low) blood pressure (all the time or in short episodes)
  • Feeling sick (with or without being sick)
  • Breathlessness
  • Depression
  • Tiredness
  • Changes in blood sugar levels

Many of the symptoms listed above are related to the high blood pressure (hypertension) that can be caused due to this 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.

Sometimes pheos 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 be because they have a condition with a risk of pheos meaning that they have regular scans to look for.

For more information, visit AMEND (UK) or Pheo Para Alliance (USA)