What Is a Hypoechoic Thyroid Nodule?

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A hypoechoic nodule is an area of swelling or abnormal cell growth on the thyroid. The term hypoechoic refers to the way that the nodule appears on an ultrasound—dark. 

When a nodule appears hypoechoic—rather than anechoic—radiologists know that it’s likely solid and not liquid-filled. A solid nodule is more likely than other types of nodules to be cancer. However, the risk is still low, and a hypoechoic nodule is more likely to be benign than it is to be cancerous. Still, your doctor will likely want to do additional testing to rule out cancer.

Causes

Thyroid nodules have a variety of causes including:

  • Irregular cell growth on the thyroid
  • Fluid-filled cysts
  • Inflammation

Unfortunately, scientists don’t know what causes any of these processes to start, or why roughly half of people have thyroid nodules. 

In some cases, doctors can identify the cause of thyroid nodules. For example:

  • A diet that is low in iodine can cause thyroid nodules, but this is very rare in the United States since salt is ionized.
  • Some thyroid diseases—including Hashimoto’s disease—can increase your risk for developing thyroid nodules

Less than 5% of thyroid nodules are cancerous. In these cases, the nodule is caused by irregular cell growth associated with the cancer. One type of thyroid cancer—medullary thyroid cancer—is linked to a hereditary genetic mutation in about 25% of cases, so if your family member has had this type of cancer, your risk of developing it is increased.

Symptoms

Oftentimes, people with thyroid nodules have no symptoms. That’s why thyroid nodules are frequently detected during medical imaging that has nothing to do with the nodule but has to do with another health concern.

How Are Thyroid Nodules Discovered?

  • In one-third of cases, a doctor finds a thyroid nodule.
  • In one-third of cases, a thyroid nodule shows up unexpectedly on a medical scan.
  • In one-third of cases, people detect their thyroid nodules themselves.

When someone discovers a thyroid nodule themselves, it may be because it is pressing on the windpipe or larynx and making it difficult to breathe or swallow. A large thyroid nodule can also lead to vocal changes or hoarseness.

In some cases, a person will be able to feel a thyroid nodule at the front of their throat (just be sure you’re not confusing the nodule for your Adam’s apple). 

how to do a thyroid neck check

Emily Roberts / Verywell

In other cases, a thyroid nodule can secrete thyroid hormones, pushing thyroid levels abnormally high. This is known as an active—or toxic—nodule. Active nodules can lead to hyperthyroidism, which has symptoms including:

  • Weight loss
  • Racing heart
  • Tremors
  • Sweating

Follow-Up Tests

Once an ultrasound shows a hypoechoic thyroid nodule, your doctor will likely do follow-up testing. Although the risks of cancer are relatively low, there is a chance that the hypoechoic thyroid nodule could be malignant. By getting a proper diagnosis and understanding of your thyroid nodule, your doctor can recommend the treatment that will be right for you. 

Your doctor will likely conduct a physical exam, feeling your thyroid nodule. This can give the doctor an idea of the size and position of the nodule.

For proper diagnosis, you’ll need to undergo follow-up tests for your hypoechoic thyroid nodule. These include:

Fine Needle Aspiration Biopsy

During a fine needle aspiration biopsy (FNA or FNAB), a doctor:

  1. Uses a needle to take cells from different areas of the thyroid nodule.
  2. The cells are examined under a microscope to determine whether there are any cancerous cells present.
  3. In most cases, the doctor will gather a few different cell samples to be sure that they find any cancerous cells that are present in the nodule.

Determining if a Nodule Is Cancerous

A biopsy is the best way to determine whether a thyroid nodule is cancerous.

A doctor may offer a local anesthetic during this is a minimally invasive procedure, but that might not even be necessary. There’s no special preparation for a biopsy, and most people have no recovery time. The peace-of-mind that a biopsy offers can be worth the nerves over the procedure. 

In 80% of cases, a fine needle aspiration biopsy will show that a thyroid nodule is not cancerous. In 5% of cases, the biopsy will show cancer.

Your doctor will be able to determine which of the four types of thyroid cancer you have by looking at the cell samples from the biopsy under a microscope.

In the remaining 15% or so of cases, a biopsy cannot provide a definitive answer about whether or not a thyroid nodule is cancerous. If that happens to you, your doctor will discuss the best course of action, which may involve surgery.

Although it’s frustrating to not get a clear answer from a biopsy, your healthcare providers will be able to continue working to find out what’s behind your hypoechoic thyroid nodule. 

Blood Test

Any time that your doctor finds a thyroid nodule—including one that is hypoechoic—they’ll likely order blood tests. The tests will measure the amount of thyroid-stimulating hormone in your blood, in order to help determine if your thyroid nodule is active, or producing hormones. 

If your doctor notes that your nodule is producing hormones, you might breathe a sigh of relief, since most active nodules are not cancerous. However, hyperthyroidism causes the body’s metabolism to increase, which can have its own health implications. The treatment for hyperthyroidism can include medication or radioactive iodine treatment to kill off your thyroid or radiofrequency ablation of the hyperfunctioning nodule.

Thyroid Scan

Hypoechoic thyroid nodules are detected via ultrasound, so if you’ve been diagnosed with one you’ve already had an ultrasound scan. However, your doctor might order another ultrasound to:

  • Get a better picture of the nodule
  • Measure size
  • Guide a biopsy needle.

Ultrasound and biopsies have become so effective that they’ve reduced the need for nuclear thyroid scans.

Yet, in some cases, especially if your thyroid nodule is active or your biopsy was inconclusive, your doctor may still want to conduct a nuclear thyroid scan to get a better picture of the nodule.

The test uses radioactive iodine to look at patterns of function in your thyroid, to help determine if your nodule is making hormones. 

If you need a nuclear thyroid scan, you’ll take a pill that contains radioactive iodine. Four to six hours after taking the pill, you’ll undergo a scan while lying on a table. Another scan is usually done about 24 hours later.

Treatment

After your doctors have a thorough understanding of your hypoechoic thyroid nodule, they’ll be able to recommend a course of treatment. That precise treatment will depend on your specific situation:

  • Whether you’ve been diagnosed with hyperthyroidism or cancer
  • The type of thyroid cancer that you have

The four types of thyroid cancer are:

  • Papillary thyroid cancer: Most thyroid cancers are papillary thyroid cancer, which has a very good prognosis because it’s unlikely to spread beyond the thyroid.
  • Follicular thyroid cancer: About 10% of thyroid cancers are follicular. They’re more likely to spread to other organs via vascular invasion (rather than the lymph nodes), and can also spread to other organs. 
  • Medullary thyroid cancer: About 2% of thyroid cancers are medullary. About 25% of this are attributed to a genetic mutation. This type of cancer can be cured with surgery.
  • Anaplastic thyroid cancer: Less than 2% of thyroid cancers are anaplastic, and they occur most often in people older than 60. This is the most aggressive form of thyroid cancer.

The common treatments used for hypoechoic thyroid nodules, including those that are cancerous, are:

Surgery

In some cases—especially if your thyroid nodule is cancerous—your doctor will recommend surgery to remove the nodule, part of your thyroid, or the entire thyroid.

Surgery is the first-line treatment for thyroid cancer. It is also recommended if a benign thyroid nodule is interfering with your ability to breathe, speak, or swallow. In some cases, it’s used for people who have hyperthyroidism. 

The type of surgery that the doctor recommends will depend on the location of your nodule, and whether it’s cancerous. Three common types of thyroid surgery are:

  • Thyroidectomy to remove all of the thyroid, or just a part, like the nodule. 
  • Thyroid lobectomy to remove the half of the thyroid that the module is on.
  • Isthmusectomy to remove just the thyroid nodule.

Radioactive Iodine Therapy

Radioactive iodine therapy, or radioiodine therapy, kills the thyroid and any cancerous cells. This is known as ablation

The thyroid is very sensitive to iodine, which other organs are not. Because of that, radioactive iodine can channel radiation and target it toward the thyroid, without harming other organs or exposing them to radiation. If you go this route you will:

  1. Swallow radioactive iodine as a solution of a capsule.
  2. After you drink the substance, the iodine will kill off your thyroid within 6 to 18 weeks.
  3. After that time, your doctor will conduct a scan to measure your thyroid function and see if the radioactive iodine treatment has worked.

In some cases, you’ll need a second course of treatment. 

Radioactive iodine therapy is used to treat thyroid cancer in some cases, and also thyroid diseases such as Grave’s disease.

Radiation Safety

People who get radioactive iodine treatment are required to quarantine at home so they don’t risk exposing anyone else to radiation.

Radiation

For certain rare types of thyroid cancer, your doctor might recommend radiation, formally known as external beam radiation therapy. Like radioactive iodine, this therapy kills cancer cells using radiation. In this case, a small beam of radiation from outside the body is carefully targeted toward the cancer. 

Radiation is used for cancers that can’t be treated with radioactive iodine, including those that have spread beyond the thyroid. Most commonly, those are cancers that don’t uptake iodine. These include:

  • Medullary thyroid cancer, which makes up about 1 to 2% of thyroid cancer cases.
  • Anaplastic thyroid cancer, which is found in less than 2% of cases.

In some cases, radiation is also used to treat other types of thyroid cancers that have not responded to radioactive iodine therapy. 

Chemotherapy

In most cases, chemotherapy is not used to treat thyroid cancer because it is not particularly useful against thyroid cancer, and more effective treatments are available.

However, if you have anaplastic thyroid cancer or papillary/follicular thyroid cancer, your doctor might recommend chemotherapy in combination with radiation. In rare cases, chemotherapy is also used to treat medullary thyroid cancer. 

Targeted Drug Therapies

If other therapies have not worked to kill off your thyroid cancers, doctors might recommend targeted drug therapies. Targeted drug therapies aim to interrupt the growth of cancer cells by blocking kinases, a protein in thyroid cancer cells that signals growth. Because of this, the drugs are known kinase inhibitors.

There are many different types of kinase inhibitors, so your doctor will recommend the one that is most effective against your specific type of cancer.

Targeted drug therapies are particularly useful for medullary and anaplastic thyroid cancer since other treatments aren’t very efficient against them. Targeted drug therapies might also be used for other thyroid cancers that haven’t responded to treatment.

Wait and See

If your hypoechoic thyroid nodule is not cancerous and is not producing enough thyroid hormone to cause hyperthyroidism, your doctor might suggest that you take a wait-and-see approach. This is common if you haven’t been experiencing any symptoms. 

In this case, you’ll likely undergo frequent thyroid scans and blood tests every 6-12 months. These scans and tests will ensure that the nodule isn’t growing or secreting hormones. If it begins to grow or become active, you doctor might advise treatment.

Undergoing your scans as recommended can ensure that any future complications with your thyroid or progression of thyroid disease are caught early. 

Life After Treatment

In many cases, treatments for thyroid cancers kill or remove the thyroid. This is good because it gets rid of the cancer. However, it also ruins your body's ability to naturally produce thyroid hormone. That can leave you with signs of hypothyroidism, or underactive thyroid. The symptoms of hypothyroidism can include:

  • Weight gain
  • Brain fog
  • Depression

To combat these symptoms and keep your metabolism functioning as normal, your doctor will likely prescribe hormone replacement medication that will be taken daily. The most common treatment for hypothyroidism is the prescription medication levothyroxine.

In order to determine that you're on the right dose and that no new symptoms of thyroid disease or cancer are emerging, your doctor will carefully monitor your thyroid health after you've been diagnosed with a hypoechoic thyroid nodule. This will involve scans and blood tests to measure your hormone levels once or twice a year.

Do Thyroid Symptoms Ever Fully Go Away?

Although thyroid disease and thyroid cancer are conditions that oftentimes have to be managed over a lifetime, it's entirely possible to live without symptoms once your doctor has you on an effective treatment protocol.

Outlook

In most cases, thyroid cancer is highly treatable. Your doctor will be able to talk about your specific outlook using the details from your case. However, data from the National Cancer Institute can help you get an idea of prognosis. 

Unlike other cancers, which use stages to signal how progressed the disease is, thyroid cancer is classed using the following designations:

  • Localized: Cancer has not spread beyond the thyroid. 
  • Regional: Cancer has spread to nearby areas, like the lymph nodes in the neck.
  • Distant: Cancer has spread to far-away organs and structures in the body. 

Using these classifications, the National Cancer Institute calculates the 5-year survival rate for each of the four types of thyroid cancers.

5-Year Survival Rate
Localized Regional Distant Overall
Papillary Near 100% 99% 76% Near 100%
Follicular Near 100% 97% 64% 98%
Medullary Near 100% 91% 38% 89%
Anaplastic 31% 10% 3% 7%

It’s important to remember that these are just statistics. Since the data was gathered about five years earlier than they were released, it’s likely that treatments for thyroid cancer have become more effective over that time, and that survival rates may have improved. This may be particularly true for hard-to-treat thyroid cancers like anaplastic thyroid cancer, since targeted drug therapies are always being improved upon. 

Speaking with your doctor about your specific case will help you understand your prognosis if you have been diagnosed with thyroid cancer. 

A Word From Verywell

Finding out that you have an hypoechoic thyroid nodule can be scary. However, before you spend too much time on stress and worry, remember that most hypechoic thyroid nodules are not cancer. Even if you call into the less than 5% of people whose hypoechoic thyroid nodules are cancerous, focus on the fact that thyroid cancer is very treatable, and the most common types have nearly 100% survival rate over five years. 

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