What Is a Thyroid Adenoma?

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The thyroid is a small, butterfly-shaped gland in the front of your throat that produces hormones affecting a number of bodily processes, from metabolism to heart rate. Thyroid disease is relatively common, and having a thyroid adenoma—a benign cyst—is one presentation of thyroid disease.

A thyroid adenoma is a noncancerous lesion on the thyroid. Although they’re not cancer, they can still affect your overall health. Thyroid adenomas can be inactive, meaning they don’t produce thyroid hormones, or active, meaning they produce hormones.

In rare cases—about 1% of people—an active thyroid adenoma can cause hyperthyroidism, or an overproduction of thyroid hormones. However, most patients with a thyroid adenoma do not have any symptoms.

Learn more about thyroid adenomas, including symptoms, diagnosis, and treatment.

woman with thyroid adenoma

Henadzi Pechan / Getty Images

Symptoms of Thyroid Adenoma 

About 7% of people have some sort of abnormal growth on their thyroids. A thyroid adenoma is one type of growth and is estimated to occur in 3% to 4% of people.

Unlike other thyroid growths—including cysts, goiters, or cancer—thyroid adenomas usually present with just one nodule rather than many.

Thyroid adenomas are not inherently harmful, and most people with thyroid adenomas don’t experience any symptoms. However, in some cases, having an active adenoma—also known as a toxic thyroid adenoma—can cause the thyroid to produce too many hormones. This can lead to symptoms of hyperthyroidism, or overactive thyroid, including:

  • Fatigue
  • Weight loss
  • Irritability, mood swings, or nervousness
  • Excessive sweating or sensitivity to heat

In addition to hyperthyroidism, people with a thyroid adenoma might experience vocal changes, hoarseness, and trouble swallowing or breathing. These symptoms occur when the thyroid adenoma is pushing against the larynx, trachea (windpipe), and other structures in the throat.

Diagnosis

Since most people don’t have symptoms of a thyroid adenoma, these lesions are often caught during medical imaging procedures for other health concerns.

After spotting an unusual growth on the thyroid, doctors need to determine whether the growth is affecting hormone levels, and whether or not it is cancerous. In order to diagnose a thyroid adenoma, doctors have to rule out other thyroid conditions that present in a similar way.

To do this, doctors will order:

This can also help determine the likelihood that a growth is cancerous since malignant and benign thyroid growths affect hormone levels in different ways.

Treatment

If you are not experiencing symptoms from your thyroid adenoma, doctors might recommend no treatment. In that case, they’ll monitor the size of the adenoma and your thyroid levels every six to 12 months to make sure any complications that arise down the line are detected early.

People whose TSH levels are impacted by a thyroid adenoma must be treated in order to restore normal thyroid function, known as euthyroid. Iodine-123 therapy is often used to kill off abnormal growths on the thyroid and restore normal thyroid function. Iodine-123 is a radioactive isotope taken by mouth.

Although Iodine-123 is radioactive, it is not harmful to thyroid cells and you do not need to take special precautions after taking it.

In some cases, where the symptoms of a thyroid adenoma are severe, your doctor might recommend surgery. This is usually used for an immediate resolution of symptoms, including hyperthyroidism or compression on the windpipe. There are three types of surgery used in patients with thyroid adenomas:

  • Thyroidectomy removes all of the thyroid, or just a part, like the adenoma.
  • Thyroid lobectomy removes the half of the thyroid that the adenoma is on.
  • Isthmusectomy removes just the isthmus.

Your doctor will consider the position and size of your adenoma, your symptoms, and any other health considerations you have in order to determine the best treatment for you.

Risk for Thyroid Adenoma

Most people have a low risk—less than 5%—of developing a thyroid adenoma. However, certain factors can increase your risk for a thyroid adenoma, including:

  • Gender: Thyroid adenomas are more common in women than men. In fact, women are at a higher risk of all thyroid disease. But if men have thyroid growths, they are more likely to be cancerous than growths in women.
  • Age: Thyroid adenomas become more common as people get older.
  • Genetics: Certain genes increase the risk for thyroid adenoma. If you have a close family member who has had a thyroid adenoma, your risk may be higher.
  • Iodine deficiency: Iodine deficiency is closely linked to the development of thyroid adenomas. However, iodine deficiency is extremely rare in the United States since salt is ionized.

A Word From Verywell

The thyroid is an underappreciated body part. Most people don’t realize its importance until something goes wrong. Having a healthy thyroid is critical to your health and well-being, so learning that you have a thyroid adenoma can be scary. Although you might not have symptoms, you should take comfort in knowing that your doctor will be monitoring your thyroid health closely going forward. This can help prevent additional complications, like changes to your voice or energy levels.

If you’ve already experienced symptoms from your thyroid adenoma, a diagnosis might bring relief. Since there is a wide range of treatment options for thyroid adenoma, you should have a candid conversation with your doctor about the benefits and drawbacks of each. That way, you can work together to decide which thyroid adenoma treatment will give you the best quality of life.

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Article Sources
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  1. Mulita, Francesk. Thyroid Adenoma. Updated February 25, 2021.

  2. MedlinePlus. Hyperthyroidism. Updated April 12, 2021.

  3. Endocrine Society. Thyroid Nodules. Updated April 2020. 

  4. American Thyroid Association. Radioactive idodine FAQ. Updated 2014.

  5. Centers for Disease Control and Prevention. Iodine level, United States, 2000. Updated November 6, 2015.