Thyroid nodules are solid or fluid-filled lumps that form within your thyroid, a small gland located at the base of your neck, just above your breastbone.
Most thyroid nodules aren't serious and don't cause symptoms. Only a small percentage of thyroid nodules are cancerous.
You often won't know you have a thyroid nodule until your doctor discovers it during a routine medical exam. Or your doctor may uncover it during a scan that was done for another health reason. Some thyroid nodules, however, may become large enough to be visible or make it difficult to swallow or breathe.
Treatment options depend on the type of thyroid nodule you have.
Your thyroid gland is located at the base of your neck, just below your Adam's apple.
Most thyroid nodules don't cause signs or symptoms. But occasionally some nodules become so large that they can:
In some cases, thyroid nodules produce additional thyroxine, a hormone secreted by your thyroid gland. The extra thyroxine can cause symptoms of an overproduction of thyroid hormones (hyperthyroidism), such as:
Only a small number of thyroid nodules are cancerous. But determining which nodules are cancerous can't be done by evaluating your symptoms alone. Most cancerous thyroid nodules are slow growing and may be small when your doctor discovers them. Aggressive thyroid cancers are rare with nodules that may be large, firm, fixed and rapid growing.
Although most thyroid nodules are noncancerous and don't cause problems, ask your doctor to evaluate any unusual swelling in your neck, especially if you have trouble breathing or swallowing. It's important to evaluate the possibility of cancer.
Seek medical care if you develop signs and symptoms of hyperthyroidism, such as:
Also see your doctor if you have signs and symptoms that may mean your thyroid gland isn't making enough thyroid hormone (hypothyroidism), which include:
Several conditions can cause nodules to develop in your thyroid gland, including:
Overgrowth of normal thyroid tissue. An overgrowth of normal thyroid tissue is sometimes referred to as a thyroid adenoma. It's unclear why this occurs, but it's not cancerous and isn't considered serious unless it causes bothersome symptoms from its size.
Some thyroid adenomas lead to hyperthyroidism.
Thyroid cancer. The chances that a nodule is cancerous are small. However, a nodule that is large and hard or causes pain or discomfort is more worrisome. You will likely want to have it checked by your doctor.
Certain factors increase your risk of thyroid cancer, such as a family history of thyroid or other endocrine cancers and having a history of radiation exposure from medical therapy or from nuclear fallout.
Enlargement of your thyroid can expand the gland well beyond its normal size and cause a noticeable bulge in your neck. This can be caused by single or multiple nodules (lumps) in your thyroid, or by an autoimmune process.
Complications associated with some thyroid nodules include:
Hyperthyroidism. Problems can occur when a nodule or goiter produces thyroid hormone, leading to an excess amount of the hormone in the body. Hyperthyroidism can result in weight loss, muscle weakness, heat intolerance, and anxiousness or irritability.
Potential complications of hyperthyroidism include an irregular heartbeat, weak bones and thyrotoxic crisis, a rare but potentially life-threatening intensification of signs and symptoms that requires immediate medical care.
In assessing a lump or nodule in your neck, one of your doctor's main goals is to rule out the possibility of cancer. But your doctor will also want to know if your thyroid is functioning properly. Tests include:
Physical exam. Your doctor will likely ask you to swallow while he or she examines your thyroid because a nodule in your thyroid gland will usually move up and down during swallowing.
Your doctor will also look for signs and symptoms of hyperthyroidism, such as tremor, overly active reflexes, and a rapid or irregular heartbeat. He or she will also check for signs and symptoms of hypothyroidism, such as a slow heartbeat, dry skin and facial swelling.
Fine-needle aspiration biopsy. Nodules are often biopsied to make sure no cancer is present. During the procedure, your doctor inserts a very thin needle in the nodule and removes a sample of cells.
The procedure is usually done in your doctor's office, takes about 20 minutes and has few risks. Often, your doctor will use ultrasound to help guide the placement of the needle. Your doctor then sends the samples to a laboratory to have them analyzed under a microscope.
Thyroid scan. Your doctor may recommend a thyroid scan to help evaluate thyroid nodules. During this test, an isotope of radioactive iodine is injected into a vein in your arm. You then lie on a table while a special camera produces an image of your thyroid on a computer screen.
Nodules that produce excess thyroid hormone — called hot nodules — show up on the scan because they take up more of the isotope than normal thyroid tissue does. Hot nodules are almost always noncancerous.
In some cases, nodules that take up less of the isotope — called cold nodules — are cancerous. However, a thyroid scan can't distinguish between cold nodules that are cancerous and those that aren't cancerous.
Treatment depends on the type of thyroid nodule you have.
If a thyroid nodule isn't cancerous, treatment options include:
Watchful waiting. If a biopsy shows that you have a noncancerous thyroid nodule, your doctor may suggest simply watching your condition.
This usually means having a physical exam and thyroid function tests at regular intervals. It may also include an ultrasound. You're also likely to have another biopsy if the nodule grows larger. If a benign thyroid nodule remains unchanged, you may never need treatment.
If a thyroid nodule is producing thyroid hormones, overloading your thyroid gland's normal hormone production levels, your doctor may recommend treating you for hyperthyroidism. This may include:
Treatment for a nodule that's cancerous usually involves surgery.
Surgery. A common treatment for cancerous nodules is surgical removal. In the past, it was standard to remove a majority of thyroid tissue — a procedure called near-total thyroidectomy. However, today more limited surgery to remove only half of the thyroid may be appropriate for some cancerous nodules. Near-total thyroidectomy may be used depending on the extent of the disease.
Risks of thyroid surgery include damage to the nerve that controls your vocal cords and damage to your parathyroid glands — four tiny glands located on the back of your thyroid that help control your body's levels of minerals, such as calcium.
After a thyroid surgery, you'll need lifelong treatment with levothyroxine to supply your body with thyroid hormone. Your thyroid specialist will help determine the correct amount to take because it may require more than hormone replacement to manage your cancer risk.
If you see or feel a thyroid nodule yourself — usually in the middle of your lower neck, just above your breastbone — call your primary care doctor for an appointment to evaluate the lump.
Often, your doctor may discover thyroid nodules during a routine medical exam. Sometimes, your doctor detects a thyroid nodule when you have an imaging test, such as an ultrasound, CT or MRI scan, to evaluate another condition in your head or neck. Nodules detected this way are usually smaller than those found during a physical exam.
Once your doctor detects a thyroid nodule, you're likely to be referred to a doctor trained in endocrine disorders (endocrinologist). To get the most from your appointment, try these suggestions: