Extra-adrenal phaeochromocytoma
Cross sectional contrast enhanced CT image showing masses (paragangliomas) in both sides of the neck.
A paraganglioma is a type of tumour that arises from the peripheral nervous system (part of the nervous system outside the brain and spinal cord), which is further divided into the sympathetic nervous system and the parasympathetic nervous system. The peripheral nervous system is involved in controlling a variety of body functions including blood pressure, heart rate, intestinal movements and urination. Paragangliomas occur most commonly in the abdomen but can also occur in the neck and chest and are related to, but are not exactly the same as, a tumour of the adrenal glands called phaeochromocytoma.
It is unclear why paragangliomas occur. However, in some cases, mutations in certain genes increase the chance that someone may develop a paraganglioma.
In many cases, paragangliomas may not cause any symptoms unless:
They grow large enough to press on other organs or spread to other organs. For example, if the tumour has spread to the bones, this may cause bone pain. In the neck (carotid paraganglioma), they may be visible as a swelling or compress the adjacent nerves such as the vagus nerve. A type of paraganglioma (glomus paraganglioma) in the middle ear may lead to hearing loss and tinnitus.
They release hormones such as noradrenaline or less commonly adrenaline into the bloodstream. The excessive levels of these hormones can cause sweating, a racing heartbeat, feelings of anxiety, headache and high blood pressure. These symptoms can be similar to panic attacks.
Paragangliomas are rare. It is estimated that one case is diagnosed every year per 300,000 people in the population. In the UK, this means approximately 200 new cases a year.
About one in four paragangliomas are inherited as part of familial paraganglioma syndrome, multiple endocrine neoplasia type 2, von Hippel-Lindau syndrome or neurofibromatosis. Defects in genes such as succinate dehydrogenase sub-units B (SDHB), C (SDHC) and D (SDHD) are known to be linked to familial paraganglioma syndrome. Mutations in the RET gene (rearranged during transfection) are also genetic causes of a paraganglioma.
The inherited forms of paraganglioma may be associated with:
Most tests for paragangliomas are done as an outpatient. To look for evidence of excessive adrenaline or noradrenaline secretion, patients may be asked to collect their urine over 24 hours or to have a blood test. Computerised tomography (CT) or magnetic resonance imaging (MRI) scans of the body are used to look for paragangliomas and any evidence of growth of the tumours.
Specialised nuclear medicine scans such as the metaiodobenzylguanidine (MIBG) or positron emission tomography (PET) scans are also sometimes used to identify paragangliomas and any evidence of spread of the tumours.
A blood test to look for gene defects may be taken if there is any suspicion of familial paraganglioma disease, usually if there is a family history or if the tumour has developed at a young age. These are usually done in outpatient clinics by genetic specialists, who will talk through the implications of the genetic testing.
Paragangliomas are usually removed by surgery. The surgery takes place as an inpatient in specialist hospitals. A special period of preparation may be required just before surgery to ensure the blood pressure is well controlled and does not rise or fall excessively. This may include admission for three days or so before the scheduled surgery for injections/oral intake of blood pressure medications.
If the paragangliomas have spread to places where it is not possible for surgery to remove the tumours (e.g. to the liver or the bones), nuclear medicine treatments such as radioactive MIBG or octreotide may be used to slow down the growth of the tumours. This treatment will usually be given as an inpatient in specialist hospitals.
Blood pressure medications (for example phenoxybenzamine, doxazosin or propranolol) are often used to block the effects of excess adrenaline or noradrenaline on the body in order to reduce and stabilise blood pressure. This may be given as tablets as an outpatient or as an injection in hospital.
After surgery, the patient’s blood pressure will be monitored to ensure it does not rise or fall excessively. Otherwise, this can lead to an increased risk of heart attack or stroke. The side-effects of surgery can include excessive bleeding, infections, pain and possible damag to any surrounding structure (solid organ, vessels etc.) around the paraganglioma.
Nuclear medicine treatments do not usually cause side-effects, but, if many treatments are given, this may cause the bone marrow to stop producing blood cells. This can cause a lack of red blood cells which carry oxygen, or a lack of white blood cells which protect against infections. However, patients given these treatments will be carefully monitored for signs of these side-effects.
The blood pressure medications can cause an excessively low blood pressure leading to fainting and feeling dizzy, particularly when standing up. Some of the medications may also cause a slightly stuffy nose and coldness of the hands and feet. In men, phenoxybenzamine may cause absent ejaculation.
Paragangliomas are usually slow-growing tumours. The outcome depends on how far the tumour has spread, but it is possible for patients, with treatment, to live for many years beyond their original diagnosis.
Last reviewed: Jan 2019
