You have four pea-sized parathyroid glands in your neck that are near or attached to the back of your thyroid. These glands release parathyroid hormone (PTH).
Parathyroid hormone helps regulate the amount of calcium in the body. If calcium levels drop too low, your parathyroid glands secrete PTH. This helps bring more calcium into your blood by taking it out of your bones and increasing how much of it is reabsorbed by your intestines. If your calcium levels get too high, your body produces less PTH.
If your parathyroid glands produce too much PTH, you have a condition called hyperparathyroidism. This is often caused by a tumor in one of your parathyroid glands. In most cases, the tumor is benign. Cancerous parathyroid tumors are rare.
Most of the symptoms of parathyroid cancer are not directly caused by the cancer itself. Instead, they result from the hypercalcemia caused by this type of cancer.
Some of these symptoms are obvious consequences of having high calcium levels in your blood and the increasing weakness of your bones. These include:
- pain in your bones
- fractured or broken bones
- kidney stones
Other symptoms are more general. You may feel:
- muscle weakness
- more thirsty than usual
You might also experience any of the following:
- frequent and excessive urination
- unexplained weight loss
- appetite loss
- stomach ulcers
- vocal changes like hoarseness
- pain in your side, back, or abdomen that doesn’t improve
- difficulty thinking clearly
Doctors don’t know exactly what causes some people to develop parathyroid cancer. There are some risk factors that make you more likely to develop this condition:
- family history of parathyroid cancer
- familial isolated hyperparathyroidism (FIHP)
- multiple endocrine neoplasia type 1 syndrome (MEN1)
FIHP and MEN1 are inherited disorders, which means they’re passed down from parent to child.
It’s important to remember that this is a very rare condition. If you have a tumor in one of your parathyroid glands, chances are good that it’s benign rather than cancerous. According to the Stanford Medicine Cancer Institute, only about 1 percent of people who are diagnosed with hyperparathyroidism have malignant tumors.
It can be very difficult for a doctor to diagnose parathyroid cancer. This is usually because it’s hard to tell the rare cancerous parathyroid tumors apart from the much more common benign parathyroid tumors.
If your doctor suspects you might have this condition, the first thing they might do is feel your neck. According to City of Hope (a California-based cancer treatment center), cancerous parathyroid tumors can be felt over 30 percent of the time.
Your doctor will also perform several blood tests. Since a tumor causes your glands to release too much PTH, your doctor will want to check the amount of PTH in your blood. High levels of PTH cause your blood calcium level to rise, so your doctor will also check your blood calcium levels.
After these tests, if your doctor still suspects parathyroid cancer, they'll perform imaging tests. Possible tests include:
- computed tomography (CT) scan
- angiogram (X-ray with special contrast dye)
- sestamibi/SPECT (single proton emission computerized tomography) scan: uses the protein sestamibi and a radioactive material to find abnormalities of the parathyroid gland)
Treating parathyroid cancer usually involves two steps: getting rid of the cancer and treating the high levels of calcium in your blood.
You’ll generally need surgery to get rid of the tumor. Even if your doctor isn’t sure whether the tumor is cancerous, they still may want to remove it.
In some cases, your doctor might not be able to tell which of your parathyroid glands has the tumor. In that case, your surgeon will need to check all your glands during the procedure to find the cancerous one.
Treating the high blood calcium levels usually involves medications. In some cases, you might need intravenous fluids.
Parathyroid cancer may metastasize (spread) to your lungs, bones, or other parts of your body. Even if the cancer doesn’t metastasize, and the surgeon removes the entire tumor, the cancer may eventually come back.