Thyroid Nodules

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Bryan Haugen, MD
James V. Hennessey, MD
Leonard Wartofsky, MD
Stephanie Fish, MD

Additional Resources
Mayo Clinic
American Thyroid Association

What are thyroid nodules and who is at risk?

A thyroid nodule is a growth of thyroid tissue or a fluid-filled cyst that forms a lump in the thyroid gland. Nodules are very common. The chances of developing nodules in the thyroid gland increase as you get older. Symptoms are not common, but a large nodule enough may cause pain or hoarseness, or get in the way of swallowing or breathing.

Doctors are concerned about thyroid nodules, because they can sometimes be cancerous. Thyroid cancer is found in about 8 percent of nodules in men (or 8 out of 100) and in 4% of nodules in women. Thus, about 90% of all thyroid nodules are benign (non-cancerous).

The cause of most benign nodules is not known, but they are often found in members of the same family. Worldwide, lack of iodine in the diet is a very common cause of nodules.

How are thyroid nodules diagnosed?

Most thyroid nodules are found during a routine physical exam. Sometimes the nodules are noted on an x-ray study that includes the neck. If a thyroid is found, your doctor will check a blood test to learn if the thyroid is functioning normally. Sometimes, a nodule can be associated with hyperthyroidism (producing too much thyroid hormone) or hypothyroidism (producing not enough thyroid hormone).

However, the blood tests are not enough to test for thyroid cancer. To gather more information about the nodule, your doctor might recommend one or more of the following tests:

  • Fine-needle aspiration biopsy uses a thin needle to remove cells or fluid samples from the nodule. This test may be recommended if the nodule is larger than 1.5 centimeters or if it has any concerning features on ultrasound. This test is very helpful for identifying cancerous or "suspicious" nodules.
  • Thyroid ultrasound is used to get an exact picture of the thyroid and see if the nodule is solid or filled with fluid (cystic). Although this test cannot tell if the nodule is cancerous, it is very useful to guide the needle to remove (aspirate) cells from nodules. This procedure is called “ultrasound-guided fine needle aspiration biopsy.”
  • Thyroid scan uses a small amount of radioactive iodine and a special camera to get a picture of the thyroid and learn if the nodule is overactive or underactive. This procedure is usually done when the blood tests show hyperthyroidism, or too much thyroid hormone. 

How are thyroid nodules treated?

Treatment depends on the type of thyroid nodule. If the fine needle aspiration shows cancerous or suspicious cells, experts usually recommend surgery to remove the thyroid gland. After surgery, radioactive iodine therapy may be used to destroy any remaining thyroid cells.

Some benign nodules may need to be removed with surgery if they are very big and are causing problems with swallowing or breathing. Most benign nodules are watched without surgery. Hyperfunctioning nodules are almost never cancerous, but they may cause hyperthyroidism, too much thyroid hormone in the body—which can lead to health problems. These nodules may be surgically removed or treated with radioactive iodine.

If surgery is not recommended, your doctor needs to monitor the thyroid nodule every 6 to 12 months. This follow-up may involve a physical exam or a thyroid ultrasound or both. If the nodule gets larger, you may need to have a repeat fine needle biopsy.

What should you do if you think you have a thyroid nodule?

If you think you have a thyroid nodule, see your doctor. Your doctor may refer you to an endocrinologist (a specialist in hormone-related conditions) for diagnosis and treatment. Then get the recommended treatment and follow up with your doctor as needed.

Questions to ask your doctor

  • What kind of nodules do I have?
  • Am I at risk for thyroid cancer?
  • What treatment do I need?
  • What are the risks and benefits of each of my treatment options?
  • Should I see an endocrinologist?

Edited: September 2017