HealthInfo Aoraki South Canterbury
Thyroid nodules
Tona repe tenga
Thyroid nodules are lumps that form inside your thyroid gland. They may be filled with fluid or thyroid tissue. They're quite common and most people who have them do not notice it until their doctor discovers them during a routine examination.
Your thyroid gland is found in the lower front of your neck. It produces thyroid hormones, which enter your blood and are carried through your body. Thyroid hormones are important because they help your body use energy and stay warm. They also keep your brain, heart, muscles and other organs working as they should.
Cancerous thyroid nodules are rare (fewer than five in every 100 people with thyroid nodules). You're at a higher risk of thyroid cancer if you:
- have a family history of thyroid or other endocrine cancers
- have a history of radiation exposure, particularly to the head and neck.
Causes of thyroid nodules
Several things can cause thyroid nodules to develop in your thyroid gland. These include:
- Thyroid cyst – Cavities that are usually filled with fluid. Sometimes solid components may be mixed with fluid in thyroid cysts.
- Iodine deficiency – A lack of iodine in your diet can sometimes cause thyroid nodules. Iodine deficiency is uncommon in New Zealand where iodine is routinely added to table salt and other foods.
- Thyroid adenoma – An overgrowth of normal thyroid tissue. It's unclear why this happens.
- Ongoing inflammation of the thyroid (thyroiditis) – A thyroid disorder called Hashimoto's disease. The inflammation can result in thyroid nodules getting larger. This is often associated with an underactive thyroid (hypothyroidism).
- Thyroid cancer.
Symptoms of thyroid nodules
Most thyroid nodules cause no symptoms at all. A nodule is usually noticed when a person feels a lump in their throat or sees it in a mirror. Sometimes your doctor may notice the swelling during a routine examination.
In rare cases, thyroid nodules may cause pain. If the nodule is large enough and positioned near your oesophagus, it can affect swallowing.
Diagnosing a thyroid nodule
Your doctor will try to determine whether the rest of your thyroid is healthy or if it's overactive (hyperthyroidism) or underactive (hypothyroidism). They will ask you questions about your symptoms and will feel your thyroid to check whether the entire gland is enlarged. They will also check whether many nodules are present or just one.
To check your thyroid gland function, your doctor will arrange blood tests to measure thyroid hormone levels. This is called a thyroid function test.
Sometimes your doctor may order more specialised tests, such as:
- an ultrasound scan – this can help your doctor measure the thyroid nodule's size and decide if it's filled with fluid or thyroid tissue
- a radionuclide thyroid scan
- a fine needle biopsy.
Treating a thyroid nodule
The treatment for a thyroid nodule depends on the diagnostic test findings and type of nodule.
If the thyroid nodule is benign (not cancer), the nodule can be left alone and watched closely to make sure it doesn't grow any larger. It may also be removed with surgery.
If the thyroid nodule is cancerous or your doctor is highly suspicious of cancer, the nodule will be removed with surgery. Most thyroid cancers can be cured and hardly ever cause life‑threatening problems.
HealthInfo recommends the following videos
- Swedish Medical Centre – What is a Thyroid Nodule?
An informative video explaining thyroid nodules and what they mean for your health and care.
HealthInfo recommends the following pages
- American Thyroid Association – Thyroid nodules
More information about what causes thyroid nodules and how they're treated.
- NHS Choices (UK) – Thyroid Cancer
Information about thyroid cancer, including symptoms, diagnosis and treatment.
Content shared between HealthInfo Canterbury, KidsHealth and Health Navigator NZ as part of a National Health Content Hub collaborative. Last reviewed July 2023.
Sources
Review key: HITHY-49064
