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 bone metabolism.

A thyroid nodule is a growth in your thyroid. Some people become aware of it because it’s hard to the touch, uncomfortable, or bothersome, interfering with the way they breathe or swallow. Many people, however, are unaware of a thyroid nodule until it is noted by a health care provider. Some nodules can be so tiny that they are only discovered incidentally during an imaging exam.

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 are more likely to be cancerous. Nodules are more common among older adults; their incidence increases as people age.

Because different health conditions are associated with thyroid nodules, there is no single treatment for them. 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, problems sleeping, difficulty concentrating, hair loss, tremor, heat intolerance, diarrhea, and weight loss.

Some thyroid nodules produce no thyroid hormone but may cause discomfort as they grow in size, while others are completely asymptomatic.

Doctors aren’t sure why thyroid nodules form. They may be caused by different underlying health conditions that involve the thyroid, including:

• Goiter
• Thyroid cysts
• Inflammation of the thyroid gland
• Thyroid adenomas
• Hashimoto’s disease
• Iodine deficiency
• Thyroid cancer

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

Other people may have:

• A lump in the front of the lower neck
• A tickle in the throat
• A hoarse voice
• Trouble swallowing
• Difficulty breathing, 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
• Weight loss
• Feeling hot or overheated
• Warm skin
• Rapid heartbeat

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

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

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

• A thyroid nodule that feels hard to the touch
• A hoarse voice
• Other voice changes
• Swollen lymph nodes 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 or Hashimoto’s disease)
• Radiation therapy for head or neck cancer
• Thyroid cancer
• A low-iodine diet
• A goiter
• A predisposition syndrome, including Multiple Endocrine Neoplasia type 2, PTEN-Harmartoma Syndrome, DICER-1 syndrome, Familial Adenomatous Polyposis, McCune-Albright syndrome, Turcot or Gardner syndrome

Sometimes, 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, offers 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 head and neck 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, such as dry skin, warm skin, hair loss, or goiter, 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, such as ultrasound, CT scan, MRI, or PET scan, to look for the presence of nodules
• Biopsy, during which the doctors 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.

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. Nodules may be destroyed by injecting them with alcohol or by directing heat at them.
• Surgery. Large, hyperfunctioning, or cancerous nodules are typically treated surgically through removal of part or all of the thyroid gland. Some patients with thyroid cancer have spread of the cancer 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 tissue and emits a small particle that can destroy the cell.

If part or all of the thyroid is destroyed or surgically removed, patients will 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 5 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.”