Parathyroid Cancer

At a Glance

  • Parathyroid cancer is the rarest of all human cancers.
  • It is important to differentiate them from non-cancerous parathyroid adenomas, which cause common endocrine problems.

What is Parathyroid Cancer?

Parathyroid cancer is a rare disease in which malignant (cancer) cells form in the tissues of a parathyroid gland. It is important to differentiate them from the parathyroid adenomas (non-cancerous tumor), which represents a common endocrine problem.

With an estimated incidence of 0.015 per 100,000 population and an estimated prevalence of .005% in the United States, parathyroid cancer is one of the rarest of all human cancers. In Europe, the United States, and Japan, parathyroid carcinoma has been estimated to cause hyperparathyroidism (HPT) in .017% to 5.2% of the cases; however, many series report this entity to account for less than 1% of patients with primary HPT.

Anatomy

The parathyroid glands are four pea-sized organs found in the neck near the thyroid gland. The parathyroid glands make parathyroid hormone (PTH or parathormone). PTH helps the body use and store calcium to keep the calcium in the blood at normal levels.

A parathyroid gland may become overactive and make too much PTH, a condition called hyperparathyroidism. Hyperparathyroidism can occur when a benign tumor (non-cancer), called an adenoma, forms on one of the parathyroid glands, and causes it to grow and become overactive. Sometimes hyperparathyroidism can be caused by parathyroid cancer, but this is very rare.

The extra PTH causes:

  • The calcium stored in the bones to move into the blood.
  • The intestines to absorb more calcium from the food we eat.

This condition is called hypercalcemia (too much calcium in the blood).

The hypercalcemia caused by hyperparathyroidism is more serious and life-threatening than parathyroid cancer itself and treating hypercalcemia is as important as treating the cancer.

Risk Factors

Anything that increases the chance of getting a disease is called a risk factor. Risk factors for parathyroid cancer include the following rare disorders that are inherited (passed down from parent to child):

  • Familial isolated hyperparathyroidism (FIHP).
  • Multiple endocrine neoplasia type 1 (MEN1) syndrome.

Treatment with radiation therapy may increase the risk of developing a parathyroid adenoma.

Symptoms

Possible signs of parathyroid cancer include:

  • Weakness.
  • Feeling very tired.
  • Nausea and vomiting.
  • Loss of appetite.
  • Weight loss for no known reason.
  • Being much more thirsty than usual.
  • Urinating much more than usual.
  • Constipation.
  • Trouble thinking clearly.

Other symptoms of parathyroid cancer include the following:

  • Pain in the abdomen, side, or back that doesn’t go away.
  • Pain in the bones.
  • A broken bone.
  • A lump in the neck.
  • Change in voice such as hoarseness.
  • Trouble swallowing.