A paraganglioma is a rare tumor that grows from clusters of nerve cells scattered throughout the body. These cell clusters, called paraganglia, are part of the nervous system and help regulate blood pressure and other automatic functions. Paragangliomas can appear almost anywhere, from the neck to the abdomen to the pelvis, and they range from slow-growing and harmless to aggressive and capable of spreading. When the same type of tumor develops specifically in the adrenal glands (small organs on top of the kidneys), it’s called a pheochromocytoma, which is essentially a paraganglioma in a specific location.
Where Paragangliomas Grow
Paraganglia are tiny organs embedded along nerve pathways from your skull base down to your pelvis. Because they’re so widely distributed, paragangliomas can show up in many places. The most common location is the head and neck region, particularly near the carotid artery in the neck (called a carotid body tumor), followed by the area around the ear (jugulotympanic paraganglioma) and along the vagus nerve. These head and neck tumors are typically linked to the parasympathetic nervous system, which controls “rest and digest” functions.
Paragangliomas also develop in the abdomen and pelvis, where they arise from sympathetic nerve chains that run alongside the spine, around the urinary bladder, and near the reproductive organs. One historically notable location is the organ of Zuckerkandl, a small structure near the base of the abdominal aorta. The location matters because it often determines whether a tumor produces hormones and what symptoms it causes.
Functional vs. Non-Functional Tumors
Some paragangliomas actively pump out stress hormones called catecholamines (adrenaline and related chemicals). These are called functional or secretory tumors, and they can cause dramatic symptoms: sudden spikes in blood pressure, a racing heart, intense sweating, headaches, and episodes of anxiety or panic. These surges can be episodic, lasting minutes to hours, and are sometimes triggered by physical activity, stress, or even certain foods.
Non-functional paragangliomas don’t produce excess hormones, which makes them harder to detect. They often grow silently for years and are discovered incidentally on imaging done for an unrelated reason, or they eventually cause symptoms by pressing on nearby structures. A paraganglioma in the neck might cause a painless lump, difficulty swallowing, or changes in voice. One near the ear can cause pulsatile tinnitus, a rhythmic whooshing sound that matches your heartbeat.
Genetics Play a Major Role
Paragangliomas have one of the strongest genetic links of any tumor. Up to 40% of cases involve an inherited gene mutation, which is unusually high compared to most cancers. The most important group of genes involved are the SDH genes (SDHB, SDHC, SDHD, and SDHAF2), which provide instructions for building an enzyme called succinate dehydrogenase. This enzyme plays a key role in how cells generate energy. When it malfunctions, cells can grow unchecked.
Each gene mutation carries a slightly different risk profile. Mutations in the SDHB gene are particularly concerning because they are associated with a higher chance of the tumor spreading to distant sites like bones or lymph nodes. Mutations in SDHD tend to cause head and neck paragangliomas, often multiple ones, and are more commonly passed from father to child due to a genetic phenomenon called imprinting. Because of these strong hereditary patterns, genetic testing is now recommended for virtually everyone diagnosed with a paraganglioma, even if there’s no obvious family history. Identifying a mutation has implications not just for the patient but for their relatives, who can then be screened early.
How Paragangliomas Are Diagnosed
Diagnosis typically starts with blood or urine tests that measure metanephrines, the breakdown products of catecholamines. A plasma test for free metanephrines has a sensitivity approaching 100%, meaning a normal result essentially rules out a hormone-producing paraganglioma. If levels are elevated, the next step is imaging to locate the tumor.
Standard CT scans and MRI are often the first imaging tools used, but a specialized nuclear medicine scan called Ga-68 DOTATATE PET/CT has become the preferred option for paragangliomas. This scan targets receptors found on the surface of these tumors and offers superior detection compared to MRI alone. It’s especially useful for finding tumors in the head and neck, identifying whether disease has spread, and distinguishing recurrent tumor from scar tissue after surgery. For non-functional tumors that don’t produce measurable hormones, imaging may be the primary path to diagnosis.
Are All Paragangliomas Cancerous?
This is where the terminology gets a bit confusing. The 2022 World Health Organization classification now considers all paragangliomas to be malignant neoplasms with a variable risk of spreading. That doesn’t mean every paraganglioma will spread. It means these tumors exist on a spectrum, and there’s no reliable way to look at one under a microscope and declare it completely benign. The only definitive proof of metastatic disease is finding tumor cells in locations where paraganglia don’t normally exist, specifically lymph nodes and bones.
In practice, most paragangliomas behave in a relatively indolent way. Patients with a small, localized paraganglioma have a five-year survival rate of about 95%, according to the National Cancer Institute. When the disease has recurred or spread, the five-year survival rate drops to between 34% and 60%. This wide range reflects how different genetic backgrounds and tumor locations influence outcomes. SDHB-mutated tumors, for example, tend to be more aggressive and require closer long-term monitoring.
Treatment Options
Surgery is the primary treatment for paragangliomas that can be safely removed. For functional tumors, careful preparation before surgery is critical because manipulating the tumor during removal can cause dangerous surges in blood pressure. Patients typically take blood pressure medications for several weeks beforehand to stabilize their cardiovascular system. Many paragangliomas in the abdomen and pelvis can be removed with minimally invasive techniques, while head and neck tumors sometimes require more complex approaches depending on how close they are to major blood vessels and nerves.
Not all paragangliomas need immediate surgery. Small, non-functional head and neck paragangliomas in older patients may be monitored with regular imaging rather than operated on, particularly if the risks of surgery (such as nerve damage) outweigh the benefits. This “watch and wait” approach relies on tracking growth over time.
For metastatic disease, treatment becomes more complex. A targeted therapy using a radioactive compound that binds to receptors on tumor cells has shown meaningful results. In a study reported by the European Society for Medical Oncology, patients treated with this approach had a median time before disease progressed of about 20 months. Patients without inherited SDH mutations did better, with a median of over 24 months, while those with SDH mutations had a median closer to 13 months. Other options for advanced disease include certain chemotherapy combinations and external radiation for symptom control.
Long-Term Monitoring
Because paragangliomas can recur years or even decades after initial treatment, lifelong follow-up is standard. This typically involves periodic blood tests for metanephrines and imaging scans at intervals that depend on the individual’s risk profile. People with known genetic mutations are monitored more frequently and may develop additional tumors over time, sometimes in entirely different locations from the original.
Family members of someone with a hereditary paraganglioma syndrome benefit from genetic counseling and, if they carry the mutation, regular biochemical and imaging screening starting in childhood or early adulthood. Early detection in these families often catches tumors before they cause symptoms or grow large enough to complicate surgery.