Patient Basics: Parathyroid Cancer

Parathyroid cancer (parathyroid carcinoma) is a rare cancer that starts in one of the small parathyroid glands in the neck. These glands make parathyroid hormone (PTH), which controls the calcium in your blood. Almost all of these cancers make too much PTH, so the first sign is often very high calcium. Most growths in a parathyroid gland are not cancer.

Key points

• Fewer than 1 in 100 people with an overactive parathyroid gland (hyperparathyroidism) have cancer. Most have a harmless growth called an adenoma.
• Symptoms usually come from high calcium: thirst, tiredness, bone pain, kidney stones and trouble thinking.
• Very high blood calcium and PTH, sometimes with a lump in the neck, raise the concern for cancer.
• Surgery to remove the tumor in one piece is the main treatment.
• It can come back years later, so regular blood tests continue for life.

What the parathyroid glands do

Most people have four parathyroid glands, each about the size of a grain of rice. They sit behind the thyroid gland in the lower front of the neck, but they are separate from it and do a different job. When the calcium in your blood drops, the glands release PTH. PTH draws calcium out of the bones, helps the kidneys hold on to calcium, and helps the gut absorb more of it from food. When calcium is back to normal, the glands slow down.

A tumor in a parathyroid gland ignores that signal. It keeps making PTH, and blood calcium keeps rising.

Parathyroid cancer symptoms

Mildly high calcium often causes no symptoms and is found on a routine blood test. With parathyroid cancer, calcium is often much higher, and symptoms tend to be stronger:

• Feeling very thirsty and urinating often
• Tiredness, weakness and aching muscles
• Bone pain, thin bones (osteoporosis) or bones that break easily
• Kidney stones, which cause sharp pain in the back or side
• Nausea, vomiting, constipation, belly pain or poor appetite
• Trouble focusing, forgetfulness, low mood or confusion

The tumor itself can cause:

• A firm lump low in the front of the neck
• A hoarse voice, if it presses on the nerve to the voice box
• Trouble swallowing

Symptoms are the same in women and men. Benign parathyroid growths are much more common in women, especially after menopause, but parathyroid cancer affects women and men about equally. It is most often found in middle age.

What causes parathyroid cancer

Most of the time, there is no clear cause. Things linked to a higher risk include:

• Changes in the CDC73 gene. An inherited change in this gene causes hyperparathyroidism-jaw tumor syndrome. People with it have a much higher chance of parathyroid cancer, along with growths in the jaw and the kidneys.
• Other inherited conditions that cause overactive parathyroid glands in several family members.
• Radiation to the head or neck in the past, which may raise the risk.

How it’s diagnosed

• Blood tests. Calcium and PTH are both high with any overactive parathyroid. The usual PTH test is called “intact PTH.” With cancer, both levels are often far higher than with a benign growth. Your doctor will also check kidney function and vitamin D.
• Urine test. This measures how much calcium your kidneys are passing.
• Imaging. A neck ultrasound, a sestamibi scan (a scan using a small amount of a tracer that parathyroid tissue takes up) or a special CT scan can show which gland is enlarged and whether it is growing into nearby tissue.
• Bone density scan. This shows whether high PTH has thinned your bones.
• Genetic testing. Testing for CDC73 changes is advised for people with parathyroid cancer, and sometimes for their relatives.

Doctors usually avoid a needle biopsy when cancer is suspected, because the needle could spread cancer cells. Instead, the diagnosis is often made after surgery, when a pathologist looks at the removed gland under a microscope. Signs of cancer include tumor growing into nearby tissue or blood vessels.

Parathyroid cancer treatment

Surgery

Surgery is the main treatment and the best chance of cure. An experienced surgeon removes the tumor in one piece, taking care not to break it open. They often remove nearby tissue too, such as the thyroid lobe on that side and any affected lymph nodes. After surgery, calcium can drop quickly as the bones soak it back up. You may need calcium and vitamin D pills for a while.

Lowering calcium

Before surgery, or if the cancer can’t be fully removed, medicines help control calcium:

• Fluids through a vein
• Cinacalcet, a pill that tells parathyroid tissue to make less PTH
• Zoledronic acid or denosumab, which slow the release of calcium from bones

Other treatments

Radiation is sometimes given after surgery. If the cancer comes back or spreads, often to the lungs, bones or liver, more surgery may help. Chemotherapy rarely works well for this cancer. Clinical trials of newer drugs may be an option.

Living with parathyroid cancer

This cancer usually grows slowly, but it comes back in many people, sometimes years after surgery. You’ll have calcium and PTH tests every few months at first, then less often. A rise can be the first sign of a return. Many people live for many years. When problems do occur, they often come from high calcium, which treatment can control.

When to see a doctor

• A blood test shows high calcium
• Ongoing thirst, tiredness, bone pain or kidney stones
• A lump in the neck, or hoarseness that lasts more than 3 weeks
• A family history of overactive parathyroid glands or parathyroid cancer

Get emergency care for confusion, severe drowsiness, repeated vomiting or an irregular heartbeat, especially if you know your calcium is high.

Common questions about parathyroid cancer

Can you feel a parathyroid tumor in your neck?

Usually not if it is benign. Adenomas are small and sit deep behind the thyroid. Parathyroid cancers tend to be larger and firmer, so a doctor can sometimes feel a lump low in the neck. A neck lump together with very high calcium needs prompt testing.

Is there a blood test for parathyroid cancer?

No single blood test proves it. Calcium and PTH are high with any overactive parathyroid gland. Very high levels make cancer more likely and lead to imaging and surgery. The final answer usually comes from looking at the removed gland under a microscope.

What is the difference between a parathyroid adenoma and cancer?

An adenoma is a benign growth. It causes most cases of overactive parathyroid, and removing it usually cures the problem. A cancer can grow into nearby tissue and spread to other organs. It is also more likely to come back after surgery.

Is parathyroid cancer a type of thyroid cancer?

No. The parathyroid glands sit behind the thyroid, but they are separate glands that make a different hormone. Thyroid cancer is common and is often found as a lump in the thyroid itself. Parathyroid cancer is very rare and usually shows up first as high calcium.

Questions to ask your doctor

• How likely is it that this is cancer and not an adenoma?
• How many parathyroid cancer surgeries has my surgeon done?
• What will happen to my calcium after surgery?
• Should my family and I have genetic testing?
• How often will I need blood tests and scans?

Learn more

• Parathyroid cancer treatment (National Cancer Institute)
• Parathyroid disorders (MedlinePlus, U.S. National Library of Medicine)

This guide is general information and doesn’t replace advice from your own doctor. Last updated October 2026.