The thyroid is a butterfly-shaped gland that sits on top of your trachea (windpipe) in your lower neck. It produces hormones that help regulate the body’s metabolism, growth, and development by playing an important role in controlling heart rate, muscle function, digestion, brain development, and, indirectly, bone metabolism.

A thyroid nodule is a growth within your thyroid. Some people become aware of it because it is visible, firm to the touch, uncomfortable, or bothersome, interfering with the way they breathe or swallow, or noticeable when swallowing. Many people, however, are unaware of a thyroid nodule until it is noted by a health care provider. Most nodules are discovered incidentally during an imaging exam performed for other reasons.

Regardless of how it presents, the existence of a nodule alone should not be worrisome. Between 50% and 65% of healthy people are found to have thyroid nodules. Many nodules don’t cause symptoms or health problems. Only 5% of nodules are linked to an overactive or underactive thyroid and only 10% of nodules are found to be cancerous.

While women are more likely than men to develop thyroid nodules, thyroid nodules in men have a higher rate of being cancerous. However, thyroid cancer is much more common in women. Nodules are more common among older adults; their incidence increases as people age.

All thyroid nodules need to be evaluated by a doctor once discovered. Sometimes, they don’t need to be treated at all and may just be observed over time. In other cases, treatments are available to manage the condition that caused the nodule, from overactive thyroid to thyroid cancer.

Each health condition has its own outcome, but overall, people who have thyroid nodules lead normal, healthy lives.

A thyroid nodule is a (hard or soft) lump that develops within the thyroid gland in the neck. The growth may be caused by a variety of conditions that affect the thyroid gland. Some people have one nodule; others have many.

The thyroid gland plays a large role in our body’s everyday functioning. The hormones it produces help control metabolism, heart rate, and breathing. When the thyroid is functioning normally, it responds to thyroid-stimulating hormone (TSH) produced by the pituitary gland (a pea-sized structure in the base of the brain) to produce the thyroid hormones thyroxine (T4) and triiodothyronine (T3), which travel through the bloodstream and have an effect on many different cell types throughout the body.

Some thyroid nodules produce too much thyroid hormone, ignoring signals from the brain (low-TSH) to decrease the amount of thyroid hormone. Those with hyperfunctioning nodules may have rapid heart rates or palpitations, problems sleeping, difficulty concentrating, hair loss, tremors, shortness of breath, headaches, heat intolerance, diarrhea, and weight loss.

Most thyroid nodules produce no thyroid hormone but may cause discomfort as they grow in size, while others are completely asymptomatic. Nodules that do not produce thyroid hormones are more likely to be cancerous than hyperfunctioning nodules.

Doctors aren’t sure why thyroid nodules form. In most cases, a single clear cause is not identified. Factors that may contribute to the formation of thyroid nodules may be caused by health exposures that involve the thyroid, include:

• Inflammation of the thyroid gland (such as Hashimoto’s disease, an autoimmune disease in which the immune system attacks and damages the thyroid, often resulting in hypothyroidism, also known as underactive thyroid)
• Iodine deficiency (depending on where you live and your diet)
• Prior ionizing radiation exposure to the neck or head
• Family risk or history of certain endocrine conditions
• Endocrine disruptors, which are substances (such as certain plastics, pesticides, and fire retardants) that can interfere with the body’s endocrine system
• Hormonal changes, especially in women

Many people who have thyroid nodules don’t experience symptoms.

Other people may have:

• A lump in the front of the lower neck
• Throat irritation or sensation of something stuck in the throat
• Voice changes
• Trouble swallowing
• Difficulty breathing or shortness of breath, especially when lying down
• Neck pain
• Jaw or ear pain
• A goiter

People who have thyroid nodules caused by an overactive thyroid (hyperthyroidism) may experience:

• Nervousness or anxiety
• Weight loss
• Feeling hot or overheated
• Warm skin
• Rapid heartbeat
• Headaches
• Fatigue
• Tremors
• Difficulty sleeping or restlessness
• Mood instability

People who have thyroid nodules associated with an underactive thyroid (hypothyroidism) may experience:

• Fatigue
• Weight gain
• Feeling cold
• Dry skin
• Hair loss
• Depressed mood

People who have thyroid nodules caused by thyroid cancer may experience:

• A thyroid nodule that feels hard to the touch
• Persistent voice change
• Swollen lymph nodes in the neck or a lump in the neck

People who are at risk of thyroid nodules in general have or have had:

• A family history of thyroid nodules or autoimmune thyroid disease (Graves’ disease, an autoimmune disease in which the immune system produces antibodies that cause the thyroid to overproduce thyroid hormone, leading to hyperthyroidism (overactive thyroid) or Hashimoto’s disease)
• Radiation therapy for head or neck cancer
• Thyroid cancer
• A low-iodine diet
• A goiter (new nodules are more likely to develop once the thyroid is enlarged or multiple nodules are present)
• A predisposition syndrome (a syndrome that increases the risk of developing a disease or disorder), including Multiple Endocrine Neoplasia type 2, PTEN-Harmartoma Syndrome, DICER-1 syndrome, Familial Adenomatous Polyposis, McCune-Albright syndrome, Turcot or Gardner syndrome

Most of the time thyroid nodules are discovered unintentionally, during an imaging study of the head and neck for another condition. If, however, a person feels a lump in their neck or notices symptoms of a nodule, the condition may be diagnosed after a doctor obtains a medical history, performs a physical exam, and orders diagnostic tests.

Talk to your doctor about any personal or family history of thyroid conditions, including thyroid cancer or another cancer that was treated with radiation therapy. You should also discuss any symptoms, such as difficulty swallowing food.

During a physical exam, your doctor will feel your neck to check for thyroid nodules. Signs of an overactive or underactive thyroid may also be assessed.

To confirm the presence of a thyroid nodule, different diagnostic tests may be used, including:

• Blood tests, which look at the levels of hormones the thyroid produces—thyroxine (T4) and triiodothyronine (T3)—as well as thyroid-stimulating hormone (TSH), which is produced by the pituitary gland, to see if a person is producing too much or not enough of these hormones
• Imaging tests, starting with an ultrasound, but can also include a computed tomography (CT) scan, magnetic resonance imaging (MRI) scan, or positron emission tomography (PET) scan, to look for the presence of nodules
• Biopsy, during which the doctor will insert a fine needle into the nodule to remove cells to determine whether the nodule is cancerous
  

Some people with thyroid nodules don’t need treatment, especially if the nodules are small and don’t cause symptoms, if they don’t have any concerning characteristics, or if the person has a negative biopsy.

However, a variety of treatments are available, depending on the cause of the nodule. For example:

• Draining. A person whose thyroid nodules are fluid-filled cysts may have the fluid drained by a needle.
• Ablation Therapy. Ablation therapy is a minimally invasive nonsurgical option that can be used to treat benign thyroid nodules that cause symptoms or are of cosmetic concern. It can also be used to treat hyperfunctioning nodules. Ablation works by destroying tissue in thyroid nodules, thereby shrinking them as the dead tissue is naturally reabsorbed by the body. Different types of ablation therapy may be used including:
  • Ethanol ablation, which involves injecting ethanol (a type of alcohol) into the nodule. This is an option for nodules that are predominantly cystic and have recurred after initial drainage.
  • Thermal ablation, which involves applying alternating electrical current that turns to heat within the thyroid nodule to destroy tissue and shrink the nodule. Examples of thermal ablation include:
    • Radiofrequency ablation (RFA), which uses high-frequency electrical current to destroy thyroid nodule tissue.
    • Microwave ablation, in which high-frequency microwaves are used to destroy nodule tissue.
    • Other forms of ablation such as laser ablation, which uses light energy, and high-intensity focused ultrasound (HIFU), which uses high-frequency sound waves, have been attempted but with mixed and inferior results to other methods of thermal ablation.
      
      During these ablation procedures, real-time ultrasound imaging is used to guide the treatment precisely at and within the thyroid nodule. Patients will be awake during the procedure but may be given a mild anti-anxiety medication to help them relax. Local numbing medication is used routinely as well.
      
      Ablation therapy may be an alternative to surgical treatment of thyroid nodules. Unlike surgery, ablation does not involve an incision or general anesthesia, and has lower risk of complications, faster return to work, and preservation of thyroid hormone function.

• Surgery. Large, hyperfunctioning, or cancerous nodules are typically treated surgically through removal of part or all of the thyroid gland. In some patients with thyroid cancer, the malignancy may have spread to nearby lymph nodes, which are also removed. Sometimes, patients undergoing treatment for thyroid cancer receive a special kind of radiation treatment post-operatively in which they drink or ingest radioactive iodine capsules. Iodine is necessary to make thyroid hormone, so the radioactive iodine travels to any microscopic sites of remaining thyroid cells and emits a small particle that destroys the cell once internalized.

If part or all of the thyroid is destroyed or surgically removed, patients could need to take a medication called levothyroxine for the rest of their lives. The drug is a synthetic form of thyroid hormone, which should help the body function properly in the absence of a thyroid gland.

People who have thyroid nodules can manage their health well. Most thyroid nodules are benign (not cancerous). Even thyroid nodules that turn out to be thyroid cancer typically are treatable. Over 90% of people (and almost 100% of young people) with thyroid cancer survive five or more years after diagnosis.

“Yale has long been a Center of Excellence in the treatment of thyroid disease with a dedicated team of specialists devoted to caring for adults and children with thyroid disease,” says Yale Medicine pediatric surgeon Emily Christison-Lagay, MD. “These include a multidisciplinary team of endocrinologists, endocrine and complex head and neck surgeons, radiologists, pathologists, nuclear medicine providers (who administer radioactive iodine), and specialist medical oncologists who assist in the treatment of rare forms of thyroid cancer. The Yale Pediatric Thyroid Center was one of the first such centers in the country developed to streamline and optimize the care of infants, children, adolescents, and young adults with all forms of thyroid disease.”

“Yale is at the forefront of offering radiofrequency ablation (RFA) for thyroid nodules, providing a nonsurgical treatment option that preserves thyroid function and improves quality of life,” says Yale Medicine endocrine surgeon Adriana Ramirez, MD. “As one of the first academic centers in the region to offer RFA, we’re able to provide personalized, minimally invasive care for patients seeking effective alternatives to surgery.”