Parathyroid adenoma

A parathyroid adenoma is a noncancerous (benign) tumor of the parathyroid glands. The parathyroid glands are located in the neck, near or attached to the back side of the thyroid gland.

The parathyroid glands in the neck help regulate calcium absorption, use, and removal by the body. They do this by producing parathyroid hormone (PTH). PTH helps regulate calcium, phosphorus, and vitamin D levels in the blood and bones. It is important for healthy bones.

Parathyroid adenomas are common. Most parathyroid adenomas do not have an identified cause. Sometimes a genetic problem is the cause. This is more common if the diagnosis is made when you are young.

Parathyroid adenomas may occur in people without a family history of the disease or as part of 3 inherited syndromes:

• Multiple endocrine neoplasia I (MEN I)
• Multiple endocrine neoplasia IIA (MEN IIA)
• Isolated familial hyperparathyroidism

In people with an inherited syndrome, a changed (variant) gene is passed down through the family. You only need to get the gene from one parent to develop the condition.

• In MEN I, problems in the parathyroid glands occur as well as tumors in the pituitary gland and pancreas.
• In MEN IIA, overactivity of the parathyroid glands occurs, along with tumors in the adrenal or thyroid gland.

Conditions that stimulate the parathyroid glands to get bigger can also cause an adenoma. These include:

• Genetic disorders
• Taking the medicine lithium
• Chronic kidney disease

Women over age 60 have the highest risk for developing this condition. Radiation to the head or neck also increases the risk.

Many people have no symptoms. The condition is often discovered when blood tests are done for another medical reason and people are found to have elevated calcium levels.

Parathyroid adenomas are the most common cause of hyperparathyroidism (overactive parathyroid glands), which leads to an increased blood calcium level. Symptoms may include any of the following:

• Bone pain or tenderness
• Confusion
• Depression and forgetfulness
• Feeling tired, ill, and weak
• Fragile bones of the limbs and spine that can break easily
• Increased amount of urine produced and needing to urinate more often (polyuria)
• Kidney stones
• Nausea and loss of appetite

Blood tests may be done to check levels of:

• Calcium
• Creatinine, BUN (kidney function tests)
• PTH
• Phosphorous
  
• Magnesium
• 25-hydroxy vitamin D
• Alkaline phosphatase

Other tests include:

• 24-hour urine test - done to determine how much calcium is being filtered out of the body into the urine 
• Bone density exam
• Kidney ultrasound or CT scan (may show kidney stones or calcification)
• Kidney x-rays (may show kidney stones)
• MRI
• Neck ultrasound
• Sestamibi neck scan (to identify the location of the parathyroid adenoma)

Surgery is the most common treatment, and it often cures the condition. For those people who cannot have surgery or choose not to, there is medical therapy with a pill. But, some people choose to only have regular checkups with their health care provider if the condition is mild.

To help improve the condition, your provider may ask you to stop taking calcium and vitamin D supplements. Women who have gone through menopause may want to discuss treatment with estrogen or other medicines to prevent bone loss.

When treated, the outlook is generally good.

Osteoporosis, which increases the risk for bone fractures, is the most common concern.

Other complications are less common, but may include:

• Calcium deposits in the kidneys that can reduce kidney function (nephrocalcinosis)
• Softened, weak areas in the bones (osteitis fibrosa)

Complications from surgery include:

• Damage to a nerve that controls your voice
• Damage to the parathyroid glands, which can cause permanent hypoparathyroidism (lack of enough PTH) and low calcium level

Contact your provider if you have symptoms of this condition.

Shonka DC, Reid LM, Russell MD. Management of parathyroid disorders. In: Francis HW, Haughey BH, Hillel AT, et al, eds. Cummings Otolaryngology: Head and Neck Surgery. 8th ed. Philadelphia, PA: Elsevier; 2026:chap 121.

Thakker RV. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 227.

Walker MD, Bilezikian JP. Primary hyperparathyroidism. In: Robertson RP, ed. DeGroot's Endocrinology: Basic Science and Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 54.

Last reviewed on: 5/20/2024

Sandeep K. Dhaliwal, MD, board-certified in Diabetes, Endocrinology, and Metabolism, Springfield, VA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.