What are thyroid nodules?
A thyroid nodule is an unusual lump (growth) of cells on your thyroid gland.
Your thyroid gland is a small, butterfly-shaped endocrine gland located in your neck, below your Adam's apple. It produces the hormones thyroxine (also called T4) and triiodothyronine (also called T3). These hormones play a role in certain bodily functions, including:
Thyroid nodules are classified as:
- Solitary (a single nodule).
- Multiple (more than one nodule).
- Cystic (fluid-filled).
More than 90% of detected nodules in adults are noncancerous (benign), but they may represent thyroid cancer in approximately 4.0% to 6.5% of cases. Even though most thyroid nodules aren’t cancer, they can sometimes be a sign of and/or cause thyroid disease.
Who do thyroid nodules affect?
Anyone can have a thyroid nodule, including children and adults. However, they’re about four times more common in people assigned female at birth than people assigned male at birth.
They also occur more often in people who live in countries in which food isn’t fortified with iodine. (Iodine is necessary for your thyroid gland to make hormones.)
Other factors that lead to an increased risk of thyroid nodules include:
- History of thyroid radiation.
- Family history of thyroid nodules or thyroid cancer.
- Increasing age.
- Iron-deficiency anemia.
- Metabolic syndrome.
- Alcohol consumption.
- Increased levels of insulin-like growth factor-1 (a hormone).
- Uterine fibroids.
How common are thyroid nodules?
Thyroid nodules are common. Healthcare providers detect them in approximately 5% to 7% of adults during a physical examination. Ultrasound imaging reveals that 20% to 76% of adults have thyroid nodules.
Thyroid nodules are less common in children.
When should I worry about thyroid nodules?
In most cases, thyroid nodules aren’t a cause for concern. But even though the vast majority of thyroid nodules are benign, some thyroid nodules do contain thyroid cancer.
For this reason, you should see your healthcare provider so they can evaluate the nodule to be sure it’s benign. As with all cases of cancer, the earlier it can be diagnosed and treated, the better.
Symptoms and Causes
What symptoms can thyroid nodules cause?
Most thyroid nodules don’t cause symptoms. However, if you have several nodules or large nodules, you may be able to see them.
In rare cases, nodules can grow big enough to cause the following symptoms:
- Trouble with swallowing or breathing.
- Hoarseness or voice changes.
- Pain in the front of your neck.
- Enlargement of your thyroid gland (goiter).
Hyperfunctioning thyroid nodules can lead to overproduction of thyroid hormones, also known as hyperthyroidism. Symptoms of hyperthyroidism include:
- Rapid heartbeat (palpitations).
- Feeling shaky and/or nervous.
- Weight loss.
- Increased appetite.
- Diarrhea and more frequent bowel movements.
- Difficulty sleeping.
- Enlarged thyroid gland (goiter).
- Light or missed menstrual periods.
Thyroid nodules may also be associated with low thyroid hormone levels (hypothyroidism). Symptoms of hypothyroidism include:
- Numbness and tingling in your hands.
- Weight gain.
- Dry, coarse skin and hair.
- Frequent, heavy menstrual periods.
What causes thyroid nodules?
Researchers don’t know why most thyroid nodules form. Nodules can form for various reasons, and there are different types, including:
- Colloid nodules: These are one or more overgrowths of normal thyroid tissue. These growths are not cancer (benign). They may grow large, but they don’t spread beyond your thyroid gland. These are the most common type of thyroid nodules.
- Thyroid cysts: These are growths that are filled with fluid or are partly solid and partly filled with fluid. Cystic nodules pose a low risk for cancer (malignancy) and are either monitored or biopsied if they’re larger than 2 centimeters.
- Inflammatory nodules: These nodules develop as a result of long-term (chronic) swelling (inflammation) of your thyroid gland. These growths may or may not cause pain.
- Multinodular goiter: Sometimes an enlarged thyroid (goiter) is made up of many nodules (which are usually benign).
- Hyperfunctioning thyroid nodules: These nodules produce extra thyroid hormone, which may lead to the development of hyperthyroidism. Hyperthyroidism requires treatment.
- Thyroid cancer: Cancer is the biggest concern when thyroid nodules form. Fortunately, thyroid cancer is very rare — it’s found in less than 6.5% of all thyroid nodules.
Diagnosis and Tests
How are thyroid nodules diagnosed?
Sometimes you can feel or see a thyroid nodule yourself, or your healthcare provider may discover it during a physical exam. Your provider may also discover a nodule with an imaging test done for another reason.
Even though thyroid nodules are almost always noncancerous (benign), the small chance that it could be cancer means that most thyroid nodules need some type of evaluation.
What tests will be done to diagnose and evaluate thyroid nodules?
Your healthcare provider may order any of the following tests to help diagnose and evaluate a thyroid nodule:
- Thyroid blood test: This test checks the levels of thyroid hormone in your blood. The hormone levels are usually normal even if you have nodules, but they can be abnormal in some cases and point to thyroid disease.
- Thyroid ultrasound: This is an imaging test that uses sound waves to create pictures of your thyroid gland. It can determine if a nodule is solid or a fluid-filled cyst. (The risk of cancer is higher in solid nodules.) This test also checks on the growth of nodules and helps find nodules that are difficult to feel. In addition, providers sometimes use ultrasound to help guide the placement of the needle during a fine-needle biopsy.
- Fine-needle biopsy: With this test, your provider uses a very thin needle to take a sample of cells from one or more thyroid nodules. They then send the samples to a laboratory for evaluation. Most nodules are noncancerous. However, if the test results are inconclusive, your provider may repeat this test. They may also suggest you have surgery to remove the nodules to make an accurate diagnosis.
- Thyroid scan: In this test, you take a small amount of radioactive iodine orally. Your provider will check to see how much of the radioactive iodine the thyroid nodules absorb and how much is absorbed by normal thyroid tissue. This will provide further information about the thyroid nodules, helping your provider determine the likelihood of cancer.
Management and Treatment
How are thyroid nodules treated?
Treatment depends on the type of thyroid nodule. Treatment options include:
- No treatment/watch and wait: If the nodules aren’t cancerous, you and your healthcare provider may decide that you don’t need to be treated at this time. You’ll see your provider regularly so they can check for any changes in the nodules.
- Radioactive iodine: Your provider may use radioactive iodine to treat hyperfunctioning thyroid nodules and goiters with several nodules. Your thyroid gland absorbs the radioactive iodine, causing the nodules to shrink.
- Surgery: Surgery to take out the nodules is the best treatment for nodules that are cancerous, cause obstructive symptoms like breathing or swallowing issues and are “suspicious” (they can’t be diagnosed without being surgically removed and examined.
Can thyroid nodules be prevented?
Since researchers don’t know what causes the majority of thyroid nodules, you can’t prevent them in most cases.
You can, however, try to decrease your risk of developing them by managing certain risk factors. For example, if you have obesity, talk to your healthcare provider about attaining a healthy weight for you. If you smoke cigarettes, try to quit. It’s also important to make sure you get enough iodine in your diet. If you use iodized table salt, you’re likely consuming enough.
Outlook / Prognosis
What is the prognosis for thyroid nodules?
The prognosis for noncancerous (benign) thyroid nodules is great. They often don’t need treatment, and only about 1% of benign thyroid nodules cause thyroid disease, which is treatable.
The prognosis for cancerous (malignant) thyroid nodules varies greatly depending on several factors, including:
- The type of cancer.
- Your age at diagnosis.
- The size of the nodule/tumor.
- If it’s spread to nearby tissues, such as lymph nodes.
- If it’s spread (metastasized) to distant parts of your body.
If you have thyroid cancer, your healthcare provider will be able to give you a more accurate prognosis.
When should I see my healthcare provider about a thyroid nodule?
If you notice a bump on your thyroid, it’s important to see your healthcare provider. Even though the majority of thyroid nodules are benign and cause no other symptoms, it’s still important to have the nodule evaluated in the small chance that it’s cancer.
If you’ve been diagnosed with a thyroid nodule and are taking the “watch and wait” approach, you’ll need to see your provider regularly so that they can monitor the nodule for any changes.
Frequently Asked Questions
How do thyroid nodules affect children?
Thyroid nodules are much less common in children than in adults, but researchers aren’t sure of the exact numbers.
There’s an increased risk of thyroid cancer in nodules found in children and adolescents compared to adults. However, over 75% of nodules found in children and adolescents are noncancerous (benign).
The symptoms, diagnosis and treatment of thyroid nodules for children are the same as for adults (as detailed in the above sections).
A note from Cleveland Clinic
Thyroid nodules are very common, and they’re usually not a cause for concern. However, it’s still important to see your healthcare provider if you notice a lump on your thyroid (in the front of your neck). They may run some tests to make sure it’s benign. If you have any questions about your risk of developing thyroid cancer or thyroid disease, talk to your provider. They’re available to help you.
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