What are thyroid nodules?
A thyroid nodule is an unusual growth (lump) of thyroid cells in the thyroid gland.
The thyroid is part of the endocrine system, which is made up of glands that secrete various hormones into the bloodstream. The thyroid is a butterfly-shaped organ (or gland) that is located on the front of the neck, just under the Adam's apple (larynx). The thyroid gland, which is made up of the right and left lobes connected to the isthmus (or “bridge), produces and releases thyroid hormones. Thyroid hormones control functions such as body temperature, digestion and heart functions.
Symptoms and Causes
What causes a thyroid nodule to form?
Sometimes the thyroid begins to grow (overgrowth), causing one or more nodules to form. Why this happens is not known. Cancer is the biggest concern when nodules form. Fortunately, cancer is very rare – it is found in less than 5 percent of all nodules. Nodules develop more often in people who have a family history of nodules, and in people who don’t get enough iodine. Iodine is needed to make thyroid hormone.
There are different types of thyroid nodules:
- Colloid nodules: These are one or more overgrowths of normal thyroid tissue. These growths are benign (not cancer). They may grow large, but they do not spread beyond the thyroid gland.
- Thyroid cysts: These are growths that are filled with fluid or partly solid and partly filled with fluid.
- Inflammatory nodules: These nodules develop as a result of chronic (long-term) inflammation (swelling) of the 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 autonomously produce thyroid hormone without regard for normal feedback control mechanisms, which may lead to the development of hyperthyroidism. Hyperthyroidism can affect the heart and cause such problems as sudden cardiac arrest, high blood pressure, arrhythmias (abnormal heart rhythm), osteoporosis and other health problems.
- Thyroid cancer: Less than 5 percent of thyroid nodules are cancerous.
How do I know if I have thyroid nodules?
Most thyroid nodules do not produce any symptoms. However, if you have several nodules, or large nodules, you may be able to see them. Although rare, nodules can press against other structures in the neck and cause symptoms, including:
- Trouble with swallowing or breathing
- Hoarseness or voice change
- Pain in the neck
- Goiter (enlargement of the thyroid gland)
Hyperfunctioning thyroid nodules can lead to overproduction of thyroid hormones, also known as hyperthyroidism. Symptoms of hyperthyroidism include:
- Muscle weakness/tremors
- Light or missed menstrual periods
- Weight loss
- Difficulty sleeping
- Enlarged thyroid gland
- Vision problems or eye irritation
- Heat sensitivity (trouble dealing with heat)
- Increase or decrease in appetite
- Shortness of breath
- Itchy skin/clammy skin
- Thinning hair
- Skin flushing (sudden reddening of face, neck or upper chest)
- Heart palpitations (rapid or irregular heartbeat)
Thyroid nodules may also be associated with low thyroid hormone levels, or hypothyroidism. Symptoms of hypothyroidism include:
- Fatigue (feeling tired)
- Frequent, heavy menstrual periods
- Weight gain
- Dry, coarse skin and hair, and hair loss
- Hoarse voice
- Trouble dealing with cold temperatures
- Generalized edema (swelling)
What are the risk factors for thyroid nodules?
Risk factors for developing thyroid nodules include:
- Family history. Having parents or siblings who have had thyroid nodules or thyroid or other endocrine cancers increases your chance of developing nodules.
- Age: The chance of developing nodules increases as you get older.
- Gender: Women are more likely than men to develop thyroid nodules.
- Radiation exposure: A history of radiation exposure to the head and neck (from medical treatments, but not from diagnostic procedures, such as a CT scan) increases your risk of developing nodules.
Risk factors for developing cancerous thyroid nodules include:
- Family history of thyroid cancer
- A nodule that is hard or is stuck to a nearby structure
- Male gender
- Age younger than 20 and older than 70
- Radiation exposure
Diagnosis and Tests
How are thyroid nodules diagnosed?
Sometimes you can feel the nodule yourself, or your doctor may discover it during an exam. However, your doctor will usually need to order one or more of the following tests:
- Thyroid hormone level test: This blood test checks the levels of hormones secreted by the thyroid gland. The hormone levels are usually normal even if there are nodules. However, there are times when abnormal hormone levels are also benign. Therefore, your doctor will probably order other tests.
- Thyroid ultrasound: This test uses sound waves to 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, thyroid ultrasound is sometimes used to help guide placement of the needle during a fine needle biopsy.
- Fine-needle biopsy of the thyroid gland: With this test, the doctor uses a very thin needle to take a sample of cells from one or more thyroid nodules. The samples are then sent to a laboratory, and most turn out to be noncancerous. However, if the test results are inconclusive, your doctor may repeat this test. The doctor may also suggest you have surgery to remove the nodules in order to make an accurate diagnosis.
- Thyroid scan: In this test, a small amount of radioactive iodine is given orally. The doctor will check to see how much of the radioactive iodine is absorbed by the nodules and how much is absorbed by normal thyroid tissue. This will provide further information about thyroid nodules, helping the doctor 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/"watchful waiting." If the nodules are not cancerous, you and your doctor may decide that you don’t need to be treated at this time. You will see your doctor on a regular basis so he or she can watch for any changes in the nodules.
- Radioactive iodine. Your doctor may use radioactive iodine to treat hyperfunctioning thyroid nodules and goiters with several nodules. The radioactive iodine is absorbed into the thyroid gland, causing the nodules to shrink. Pregnant women and women trying to become pregnant should not have this treatment.
- Surgery. Surgery to take out the nodules is the best treatment for nodules that are cancerous, cause "obstructive symptoms" (for example, are so large that they make breathing or swallowing difficult), and are “suspicious” (they cannot be diagnosed without being taken out and examined).
What do you do when your child has a thyroid nodule?
The first step if your child has a thyroid nodule is to get an ultrasound. This will help your healthcare provider assess the quality of your child’s nodule and determine if additional workup is needed. In some cases a repeat ultrasound is needed, and in some cases a biopsy. This all depends on what it looks like on the ultrasound. Some nodules require labs to look at how the thyroid is functioning.
What does a thyroid fine needle aspiration (FNA) or biopsy entail?
In some situations this is performed with local anesthesia in the clinic. Your child will be awake. In very young children the FNA is done in the operating room under general anesthesia. The pathologist will look at the tissue to determine what they thyroid nodule is composed of and if additional workup or surgery is needed. It often takes about one to two weeks to get the results.
What if the nodule is cancer?
In most cases, thyroid cancer is treated with surgery alone. In children, most of the time, the entire thyroid gland is removed. In some cases, lymph nodes may need to be removed as well. In other cases, radioactive iodine is needed after surgery to get rid of microscopic thyroid tissue.
What are the risks of removing the thyroid gland?
Behind your child’s thyroid gland runs the recurrent laryngeal nerves that help to move the vocal folds and the parathyroid glands which help regulate their body’s calcium levels.
Some of the major risk factors following the removal of the thyroid gland are:
- A “hoarse/breathy” voice.
- Low calcium levels.
After surgery your child will need to take a medication to supplement the thyroid function and in some cases a medication to keep calcium levels elevated.
Other risk factors include:
- A scar on the neck.
- Fluid collection under the skin.
- The need for future procedures such as removal of the lymph nodes from the neck.
What kind of follow-up will be needed if my child has a thyroidectomy and thyroid cancer?
You will see your child’s endocrinologist and head and neck surgeon one week after surgery. Expect to have labs done to assess calcium levels. Thyroid function labs will be drawn four weeks after surgery. Depending on the pathology, additional imaging may be obtained to see if radioactive iodine is needed. Some types of thyroid cancer will require regular blood work screening and scheduled ultrasounds.