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What Are Thyroid Nodules?

From causes and symptoms to diagnosis and treatment, the information you need about these common growths

Thyroid nodules are abnormal overgrowths of tissue in the thyroid gland that are most often benign, though in some cases (less than one in 20) they can be cancerous. Some people have one nodule, while others have many. Thyroid nodules may be solid tissue or filled with blood or other fluid.

Thyroid nodules are quite common, with as many as half of all people having at least one nodule by the age of 60. They’re particularly prevalent in women, though men can get them too, especially as they age.

In This Article: Background | Thyroid Nodule Symptoms | Causes & Risk Factors | Diagnosis | Treatments | Fast Facts | Frequently Asked Questions

 

A Quick Review of the Thyroid Gland

The thyroid is a butterfly-shaped gland about two inches long located in the base of your neck. This gland plays a huge role in your body, as it’s responsible for releasing hormones that control metabolism — the way your body uses energy. Hormones secreted by the thyroid regulate a host of body functions including your heart rate, breathing, body temperature, nervous system function, and much more.

When something is amiss with your thyroid, it can throw virtually every body system (not to mention your mood) out of whack. Thankfully, nodules on your thyroid are often harmless, causing no change in how the gland functions. When they do cause problems, effective treatments are available.  

Medical drawing of a thyroid gland with and without a nodule on it.

 Symptoms of Thyroid Nodules

Thyroid nodules usually do not cause symptoms. For this reason, they’re often found by a healthcare provider during a routine neck examination or an imaging test done for another reason (such as parathyroid disease, trauma, carotid artery disease, or cervical spine pain).

When thyroid nodules do produce symptoms, the most common are a lump in the neck and a sense of mass while swallowing (and possibly difficulty swallowing). In addition, larger nodules may cause difficulty breathing, hoarseness, and neck pain.

Rarely, the tissue in a thyroid nodule makes too much of the thyroid hormones triiodothyronine (T3) and thyroxine (T4), which can lead to symptoms of hyperthyroidism (overactive thyroid). These include:

  • Anxiety
  • Irritability or moodiness
  • Nervousness, hyperactivity
  • Sweating or sensitivity to high temperatures
  • Rapid heart rate
  • Hand trembling (shaking)
  • Hair loss
  • Frequent bowel movements or diarrhea
  • Weight loss
  • Missed or light menstrual periods

What Causes Thyroid Nodules?

The cause of thyroid nodules is often unknown. They sometimes run in families, meaning that they may have a genetic basis. Nodules can also stem from iodine deficiency, but this is rare in the United States.

Rarely — in fewer than 5% of people with thyroid nodules — cancer is the cause of the overgrowth of tissue, which is why it is important to see a doctor if you think you have a nodule.

There are several known risk factors for thyroid nodules. They are more common in women in men, and incidence increases with age. You are also at higher risk for thyroid nodules if you have been exposed to radiation or have Hashimoto’s disease, also known as Hashimoto’s thyroiditis, which is the most common cause of hypothyroidism (underactive thyroid).

How Are Thyroid Nodules Diagnosed?

Your doctor can detect a thyroid nodule by examining your neck to feel your thyroid gland. If a nodule is discovered during the physical exam, your doctor will need to answer these four questions to determine what (if anything) to do about it:

  • Is the nodule cancerous?
  • Is the nodule causing trouble by pressing on other structures in the neck?
  • Is the nodule making too much thyroid hormone?
  • Does anything need to be done about the nodule?

Here are tests your doctor may use to learn more about your thyroid nodule(s) and determine what to do next.

Ultrasound

A thyroid ultrasound can show your doctor how large the thyroid nodule is, where it’s located, and what characteristics it has. You may also have an ultrasound of the lymph nodes in your neck, which can help determine if cancer is present.

Blood Tests

Your doctor may take a blood sample to measure levels of T3 and T4 — the thyroid hormones — as well as your level of thyroid-stimulating hormone (TSH). TSH is a hormone made by the pituitary gland that regulates the thyroid's production of T3 and T4.

These blood tests can help determine if your thyroid nodule is producing excessive amounts of thyroid hormone, potentially leading to hyperthyroidism. Such nodules are almost always benign (non-cancerous).

Biopsy

If a nodule is greater than 1 cm (about one-half inch) in size, a fine needle aspiration biopsy (FNA) may be done. (Smaller thyroid nodules generally aren’t biopsied.)

The biopsy involves using a very small needle to capture a sample of cells from the nodule. The procedure is generally uncomfortable, but not painful. To help reduce your discomfort, your doctor may numb the skin area with a topical anesthetic, which is a cream that contains short-acting pain medication.

Pathologists who are experts at looking at thyroid cells under a microscope, called thyroid cytopathologists, will examine the cells to determine whether the nodule is benign or malignant (cancerous). 

Thyroid Nodule Treatments

Treatment for a thyroid nodule will depend on whether the nodule contains cancerous cells or is causing other problems, like neck discomfort or excessive production of thyroid hormones. In many cases, you won't need any formal treatment at all.

Treatment of Non-Cancerous Nodules

If your nodule falls into this category and isn’t causing any other issues, your doctor will simply monitor you with a thyroid ultrasound and physical exam at least once a year. You may also have periodic tests to check your thyroid hormone levels.

If the nodule continues to grow or causes breathing/swallowing problems or develops cancerous features over time, your doctor may recommend having it surgically removed.

Treatment of Cancerous Nodules

If the nodule has cancer cells, it will almost definitely require surgery.  There are two main surgical options: total removal of the thyroid gland, called total thyroidectomy, or removing just the half of the gland that has the nodule on it (thyroid lobectomy).

Read more about total thyroidectomy and thyroid lobectomy

Risks of thyroid surgery include damage to the nerves of the voice box and the glands that control calcium. To maximize your chance of a good outcome, look for an experienced surgeon who specializes in thyroid cancer surgery and does a high volume of such procedures.

Treatment of Nodules That Are Overproducing Thyroid Hormone

Nodules that produce too much T3 and T4 may be treated in several ways: radioactive iodine, alcohol ablation, or surgery to remove the nodule and thus cure the excess hormone production.

Radioactive iodine is given as a pill and causes the thyroid gland to shrink and make less thyroid hormone. Radioactive iodine is only absorbed by the thyroid gland, so it does not harm other cells within your body.

Alcohol ablation involves injecting alcohol into the thyroid nodule(s) using a very small needle. The treatment causes the nodules to shrink and make less thyroid hormone.

Fast Facts About Thyroid Nodules

  • Thyroid nodules are three times more common in women than in men
  • The incidence of thyroid nodules increases with age
  • At age 30, 30% of women will have a thyroid nodule, compared to one in 40 men (2.5%) the same age
  •  50% of 50-year-old women will have at least one thyroid nodule
  •  60% of 60-year-old women will have at least one thyroid nodule
  • 70% of 70-year-old women will have at least one thyroid nodule

Thyroid Nodule FAQs

What percentage of thyroid nodules turn out to be cancerous?

Fewer than 5% of all thyroid nodules are cancerous. In particular, thyroid nodules that are “purely cystic” — that is, they are filled with fluid rather than thyroid tissue—are nearly always benign (non-cancerous growths).

What types of healthcare professionals treat thyroid nodules?

Endocrinologists and thyroid specialist surgeons deal with these problems on a regular basis. But many family practice physicians, general internists, general surgeons, and otolaryngologists (also known as ear-nose-throat doctors or ENTs) are also adept at addressing thyroid nodules. The important thing is that the physician be experienced with and comfortable evaluating and treating this condition.

Are thyroid nodules hereditary?

They do run in families, suggesting that there may be a genetic component to them. But you can still develop a thyroid nodule even if nobody else in your family has had one. In other words, genes are only one of several known risk factors for thyroid nodules.

Are thyroid nodules ever surgically removed for reasons other than cancer?

Yes. Surgery might be considered if a nodule is large and causing a visible mass in your neck, or if it’s pressing on your windpipe or esophagus (swallowing tube), which can cause discomfort or difficulty breathing or swallowing. In cases where a thyroid nodule is cranking out excess amounts of thyroid hormone, surgically removing the nodule can cure the hormone overproduction. 

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