Thyroid nodules Tona repe tenga
Thyroid nodules are lumps that form inside your thyroid gland in your neck. They are common and usually harmless. Rarely, thyroid nodules may be cancerous.
Causes of thyroid nodules
Your thyroid gland is found in the lower front of your neck. It produces thyroid hormones, which are important to help your body use energy and stay warm. They also keep your brain, heart, muscles and other organs working as they should.
Several things can cause thyroid nodules to develop in your thyroid gland.
- Thyroid cyst — cavities that are usually filled with fluid but sometimes contain some solid tissue.
- Iodine deficiency — a lack of iodine in your diet can sometimes cause thyroid nodules. Iodine deficiency is uncommon in Aotearoa New Zealand where iodine is routinely added to salt and most breads.
- Thyroid adenoma — an overgrowth of normal thyroid tissue. It is 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.
Cancerous thyroid nodules are rare. They happen in fewer than 5 in every 100 people with thyroid nodules.
Symptoms of thyroid nodules
Most thyroid nodules cause no symptoms at all. You may notice a nodule when you feel a lump in your throat or see it in a mirror. Sometimes your healthcare provider 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 food pipe (oesophagus), it can affect your swallowing.
Diagnosing a thyroid nodule
Your healthcare provider will ask you about your symptoms and examine your neck.
They will try to determine whether the rest of your thyroid is healthy or if it is overactive (hyperthyroidism) or underactive (hypothyroidism).
To check your thyroid gland function, your healthcare provider will arrange blood tests to measure your thyroid hormone levels. This is called a thyroid function test.
Sometimes your healthcare provider may order more specialised tests, such as:
- an ultrasound scan to help measure the size of the thyroid nodule and decide if it is filled with fluid or thyroid tissue
- a radionuclide thyroid scan
- a fine needle biopsy.
Treating thyroid nodules
The treatment for a thyroid nodule depends on the type of nodule.
If the thyroid nodule is benign (not cancer), it can be left alone and watched closely to make sure it does not grow any larger. It may also be removed with surgery.
If the thyroid nodule is cancerous or your healthcare provider suspects it may be cancer, the nodule will be removed with surgery. Most thyroid cancers can be cured and hardly ever cause life‑threatening problems.