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It is a type of tumor that arises from the peripheral nervous system (part of the nervous system outside the brain and spinal cord ).
It is also divided into the sympathetic nervous system and the parasympathetic nervous system.
The peripheral nervous system controls a variety of bodily functions that include blood pressure, heart rate, bowel movements, and urination.
Paragangliomas occur most often in the abdomen, but they can happen in the neck and thorax and are related. Still, they are not the same as a tumor of the adrenal glands called pheochromocytoma.
What causes paragangliomas?
It is not clear why paragangliomas occur. However, in some cases, defects in specific genes increase the chances of someone developing a paraganglioma.
What are the signs and symptoms?
In many cases, paragangliomas may not cause any symptoms unless:
They grow large enough to press other organs or spread to other organs. For example, if the tumor has spread to the bones, this can cause bone pain.
The neck (carotid paraganglioma) can be seen as swelling or compressing adjacent nerves, such as the vagus nerve. A type of paraganglioma ( glomus paraganglioma ) in the middle ear can cause hearing loss and tinnitus.
They release hormones such as noradrenaline or, less frequently, adrenaline into the bloodstream. Excessive levels of these hormones can cause sweating, rapid heart rate, feeling anxious, headaches, and high blood pressure. These symptoms can be similar to panic attacks.
How common are paragangliomas?
Paragangliomas are rare. It is estimated that one case is diagnosed every year for every 300,000 people.
Are they hereditary?
Approximately one in four paragangliomas is inherited from familial paraganglioma syndrome, multiple endocrine neoplasia type 2, von Hippel-Lindau syndrome, or neurofibromatosis.
It is known that defects in genes such as the subunits of succinate dehydrogenase B (SDHB), C (SDHC), and D (SDHD) are related to the familial paraganglioma syndrome.
Hereditary forms of paraganglioma may be associated with:
- Younger age at the time of diagnosis.
- Family history of adrenal or renal tumors.
- Family history of pheochromocytoma.
- Sudden unexplained death at an early age.
How are paragangliomas diagnosed?
The majority of paraganglioma tests are performed on an outpatient basis. To look for evidence of excessive adrenaline or norepinephrine secretion, patients may be asked to collect their urine for 24 hours or to have a blood test.
Computed tomography (CT) or magnetic resonance imaging (MRI) of the body is used to look for paragangliomas and any evidence of tumor growth.
Specialized nuclear medicine scans such as metaiodobenzylguanidine (MYBG) or positron emission tomography (PET) scans are sometimes used to identify paragangliomas and any evidence of tumor spread.
A blood test may be taken to detect genetic defects if there is a suspicion of familial paraganglioma, usually if there is a family history or if the tumor has developed at a young age.
Typically, genetics specialists do it in outpatient clinics, which will discuss genetic testing implications.
Treatment
Paragangliomas are usually removed by surgery. The surgery is performed as an inpatient in specialized hospitals. A particular preparation period may be required just before surgery to ensure that blood pressure is well controlled and does not rise or fall excessively.
This may include admission for three days or so before the surgery is scheduled for injections of blood pressure medications.
If paragangliomas have spread to places where surgery is not possible to remove tumors (e.g., to the liver or bones), nuclear medicine treatments such as radioactive MYBG or octreotide may be used to slow the growth of tumors.
This treatment will usually be administered as an inpatient at specialized hospitals.
Blood pressure medications (e.g., phenoxybenzamine, doxazosin, or propranolol) are often used to block the effects of excess adrenaline or noradrenaline in the body to reduce and stabilize blood pressure. This can be given in tablets as an outpatient or an injection in the hospital.
Is there any side effect in the treatment?
After surgery, the patient’s blood pressure will be checked to ensure it does not rise or fall excessively. Otherwise, this can lead to an increased heart attack or stroke risk. Side effects of surgery can include excessive bleeding, infections, and pain.
Nuclear medicine treatments usually do not cause side effects, but if many treatments are given, this can cause the bone marrow to stop producing blood cells.
This can cause a lack of red blood cells that carry oxygen or a lack of white blood cells that protect against infections. However, patients receiving these treatments will be carefully monitored for signs of these side effects.
Blood pressure medications can cause external blood pressure that causes fainting and dizziness, especially when standing.
Some medications can also cause a stuffy nose and coldness in the hands and feet. In men, phenoxybenzamine can cause absent ejaculation.
What are the long-term implications of paragangliomas?
Paragangliomas are usually slow-growing tumors. The outcome depends on how far cancer has spread, but patients with treatment may live many years beyond their original diagnosis.
Alternative names for paraganglioma
- Extra adrenal pheochromocytoma.
