Parathyroid Cancer

Overview

Parathyroid cancer is a rare malignancy of one of the four tiny parathyroid glands, which sit behind the thyroid in the neck. These glands produce parathyroid hormone (PTH), which controls the level of calcium in the blood. When a parathyroid gland becomes cancerous, it usually overproduces PTH, driving blood calcium to very high levels.

Most of the harm from parathyroid cancer comes not from the tumor spreading but from the effects of severely high calcium (hypercalcemia) on the bones, kidneys, and nervous system. Because it is rare and resembles the far more common benign overactivity of the glands, diagnosis can be challenging. Early, complete surgical removal offers the best chance of cure.

Because it grows slowly in many cases and chiefly causes harm through high calcium, the focus of care is twofold: removing the tumor completely and controlling the calcium level in the blood. Even after successful surgery, regular long-term monitoring is needed because the cancer can return years later.

Symptoms

Symptoms are mostly due to the high blood calcium caused by excess parathyroid hormone, and they tend to be more severe than in benign parathyroid overactivity.

• Excessive thirst and frequent urination
• Fatigue, weakness, and difficulty concentrating
• Bone pain and fragile bones that fracture easily
• Kidney stones and kidney problems
• Nausea, vomiting, constipation, and loss of appetite
• Muscle weakness and, in severe cases, confusion

A firm lump in the neck is sometimes felt, which is unusual in benign parathyroid disease. Very high calcium can become a medical emergency.

Causes

The exact cause of most parathyroid cancers is not known. They arise when cells in a parathyroid gland develop genetic changes that cause uncontrolled growth and excess hormone production.

A small number of cases are linked to inherited genetic syndromes, including hyperparathyroidism-jaw tumor syndrome and multiple endocrine neoplasia. Prior radiation to the neck and long-standing kidney disease may also be associated in some people. In most cases, however, no clear cause is identified.

Risk Factors

• Inherited syndromes such as hyperparathyroidism-jaw tumor syndrome
• Multiple endocrine neoplasia (MEN) syndromes
• Previous radiation exposure to the head or neck
• Long-standing chronic kidney disease in some cases

Diagnosis

Parathyroid cancer can be hard to distinguish from benign overactivity before surgery, and the diagnosis is often confirmed afterward:

• Blood tests: Markedly high calcium and very high parathyroid hormone levels raise suspicion.
• Imaging: Ultrasound, sestamibi scans, CT, or MRI help locate the abnormal gland and check for spread.
• Surgery and pathology: Examination of the removed tissue under a microscope confirms whether it is cancer.

A neck lump, very high calcium and PTH, or signs of bone and kidney damage all increase the suspicion of cancer rather than benign disease.

Treatment

Surgery is the cornerstone of treatment, and complete removal at the first operation gives the best outcome.

• Surgery: Removing the cancerous gland together with surrounding tissue, sometimes including part of the thyroid, in one block to avoid leaving cancer cells behind.
• Lowering calcium: Fluids and medicines are used to control dangerously high blood calcium before and after surgery.
• Radiation or repeat surgery: May be considered for cancer that returns or cannot be fully removed.
• Long-term monitoring: Regular calcium and PTH measurements to detect recurrence early.

Managing the high calcium is often as important as treating the tumor itself, and a team that includes endocrine surgeons and hormone specialists usually directs care.

Follow-Up and Monitoring

• Attend regular follow-up with calcium and parathyroid hormone testing, as recurrence can occur years later
• Stay well hydrated and follow advice on calcium and vitamin D intake
• Report a return of symptoms such as bone pain, kidney stones, or excessive thirst promptly
• If an inherited syndrome is found, family members may benefit from genetic counseling and screening

When to See a Doctor

See a doctor if you have a firm lump in the neck, unexplained kidney stones, fragile bones, or symptoms of high calcium such as excessive thirst, frequent urination, fatigue, or constipation.

Seek emergency care for severe confusion, extreme weakness, persistent vomiting, or a sharp decline in alertness, which can be signs of a calcium crisis from very high blood calcium and need immediate treatment.

Related Topics

Frequently Asked Questions

References

1. National Cancer Institute (NCI). Parathyroid Cancer Treatment.
2. Mayo Clinic. Hyperparathyroidism.
3. MedlinePlus, U.S. National Library of Medicine. Parathyroid cancer.
4. American Cancer Society. Parathyroid cancer.