What causes a pheochromocytoma?
In about one-third of cases, there is a hereditary tendency to develop pheochromocytomas. The tumour is caused by an error (mutation) in the genetic makeup or DNA.
A pheochromocytoma or paraganglioma can be part of a genetic disease such as multiple endocrine neoplasia (MEN) type 2 syndrome, neurofibromatosis, Von Hippel-Lindau disease or a familial paraganglioma syndrome.
Pheochromocytomas are usually benign tumours, but in 10 to 15% of cases they are malignant. In the case of paragangliomas, on the other hand, between 20 and 50% can be malignant.
How frequently do pheochromocytomas occur?
Pheochromocytomas affect 2 to 8 in every million people each year. Paragangliomas affect 1 in every 2 million people each year. This means that there are between 40 and 130 new patients each year in the Netherlands.
What are the consequences of a pheochromocytoma?
The signs and symptoms can vary widely from person to person. On the one hand they are caused by the excess stress hormones that are being produced by the tumour, and on the other hand because of the pressure that the tumour is causing to surrounding tissue.
The excess stress hormones can cause symptoms such as:
- Raised blood pressure
- Dizziness and feeling unwell, due to a reduction in blood pressure when standing up (orthostatic hypotension)
- Excess sweating
- Hot flushes
- Palpitations or a tightness in the chest
- Anxiety or panic
- Nausea and vomiting, weight loss
- High blood sugar levels
Blood pressure can suddenly become very high, triggered for instance by a surgical operation, taking certain medicines or eating certain foodstuffs. This can lead to a heart attack, stroke, reduced consciousness (encephalopathy), cardiac arrhythmia, heart failure, fluid behind the lungs (pulmonary oedema), and sometimes to death.
Because of its size, and possible in-growth and pressure on other tissues, the tumour can also give rise to other symptoms. This depends on the location of the tumour and its size. Examples of the symptoms that can then occur are reduced hearing, tinnitus, hoarseness, pain, poor bowel movement (constipation) and coughing.
The disease can also be diagnosed by coincidence without any of these symptoms being noticed.
People with a pheochromocytoma or paraganglioma have a greater chance of developing cardiovascular disorders and diabetes mellitus.
How is a pheochromocytoma diagnosed?
If there is a suspicion that there might be a pheochromocytoma or a paraganglioma, tests will first be carried out to check whether there is a high level of stress hormones. This can be tested in the blood or from a 24-hour collection of urine. The tests determine the levels of waste products from the stress hormones: metanephrines and normetanephrines. Before the tests can be carried out, however, the person in question might first have to cease taking certain medication or adjust the dosage, because of the effect it could have on the results of the test.
Medical imaging technology such as a CT scan, an MRI scan, an MIBG scan or a PET CT scan will be used to determine the exact location of the tumour or tumours.
How is a pheochromocytoma treated?
Both pheochromocytomas and paragangliomas are treated surgically. Depending on the size and the location of the tumour, doctors will opt for keyhole surgery (laparoscopy) or an open operation.
During the operation, the tumour might produce stress hormones and this could lead to very high blood pressure and/or to massive fluctuations in blood pressure. For that reason, patients will take medication to lower their blood pressure before the operation. This pre-operative treatment usually begins two weeks before the operation. Patients are also ‘salt-loaded’ (i.e. given extra salt) during this same period, and an intravenous saline solution is administered shortly before the operation.
After the operation, tests are carried out to determine whether or not there is still a raised level of stress hormones. This can again be tested in the blood or from a 24-hour urine collection.
In some cases, the tumour can recur after removal; metastases can also occur. For that reason, patients will continue to be monitored after such an operation: they will attend an out-patient clinic every year for the blood or 24-hour urine collection testing to be repeated.