Parathyroid cancer

Facts

Parathyroid cancer is very rare. Most cases of parathyroid disease, including almost all cases of overactive parathyroid, are not cancer. At Seattle Cancer Care Alliance (SCCA), our endocrine tumor specialists — all UW Medicine doctors — have experience evaluating and treating people whose disease is cancer related.

What is parathyroid cancer?

You have 4 parathyroid glands in your neck — 2 near each half of your thyroid gland. Normally each parathyroid gland is about the size of a grain of rice. They make and release parathyroid hormone (PTH), which helps maintain a healthy level of calcium in your blood.

Cancer in a parathyroid gland usually causes a high level of PTH (overactive parathyroid, or hyperparathyroidism). This leads to a high level of calcium in your blood (hypercalcemia). High blood calcium can be dangerous, and it requires treatment.

Typically cancer develops in only 1 of the 4 parathyroid glands. 

Symptoms

Hypercalcemia from parathyroid cancer can lead to a range of symptoms. But the symptoms are not always obvious. They can include:

  • Tiredness
  • Weakness
  • Frequent urination 
  • Increased thirst
  • Nausea and vomiting
  • Constipation
  • Loss of appetite
  • Unexplained weight loss
  • Trouble thinking
  • Bone pain

If cancer causes a parathyroid gland in your neck to grow, you may have somewhat different symptoms, such as these:

  • Lump in the neck
  • Hoarseness
  • Trouble swallowing or speaking
  • Shortness of breath

Diagnosing

If your doctor suspects you might have parathyroid cancer, the doctor will examine you, ask about your medical history and ask for tests, such as:

  • Blood tests — including tests to check the level of parathyroid hormone and calcium in your blood
  • Imaging studies — such as a radionuclide (sestamibi) parathyroid scan, computed tomography (CT) scan or ultrasound 
  • Genetic testing — to check for mutations that are common in people with parathyroid cancer

Risk factors

Most of the time, there’s no clear cause for parathyroid cancer. The following inherited disorders may increase your risk:

  • Familial isolated hyperparathyroidism (FIPH), in which parathyroid tumors lead to excess parathyroid hormone
  • Hyperparathyroidism-jaw tumor syndrome, which causes overactive parathyroid glands and tumors that usually are benign but sometimes are cancerous
  • Multiple endocrine neoplasia, which can affect the parathyroid glands as well as other glands that make hormones 

Having radiation therapy to your neck can also increase your risk for parathyroid cancer.