A thyroid nodule is a localised growth or lump that forms within the thyroid gland at the front of the lower neck. Nodules are very common and in most people cause no symptoms at all, being noticed during an examination or imaging done for another reason. The great majority of nodules are benign; what matters is correctly identifying which nodule needs close follow-up or further investigation.
What is a thyroid nodule?
The thyroid is a butterfly-shaped gland lying in front of the windpipe (trachea) that produces the hormones regulating the body’s energy balance. A nodule is an area within the gland’s tissue that differs from the normal. Nodules may be fluid-filled (cystic), solid or a mixture of both; there may be a single nodule, or several nodules throughout the gland (multinodular goitre). Iodine deficiency, inflammation of the thyroid (thyroiditis), a family tendency and previous radiation to the neck region may play a role in the formation of nodules.
Symptoms
Most nodules cause no symptoms. When symptoms do occur, they may include:
- A swelling at the front of the neck that can be felt by hand or noticed in the mirror
- With large nodules, difficulty swallowing or a feeling of pressure or fullness in the throat
- Rarely, hoarseness or shortness of breath
- If the nodule produces excess hormone, palpitations, weight loss, irritability or intolerance of heat
Diagnosis
Assessment usually begins with an examination and a thyroid ultrasound. Ultrasound shows the nodule’s size, internal structure, margins and features such as calcification; these features guide the assessment of whether the nodule is suspicious. Measuring thyroid hormone levels in the blood shows how the gland is functioning. Nodules with suspicious features on ultrasound, or above a certain size, are sampled by fine-needle aspiration biopsy; this is performed under ultrasound guidance with a thin needle, takes a few minutes and allows the cells to be examined under the microscope. In nodules that produce excess hormone, a thyroid scan (scintigraphy) may also be requested.
Treatment options
Treatment is planned according to the biopsy result, the size of the nodule, the symptoms and how the gland is functioning:
- Monitoring: Benign nodules that cause no symptoms are followed with ultrasound at set intervals; for most nodules this is all that is needed.
- Surgery: Removal of one lobe or of the whole thyroid may be recommended for nodules in which the biopsy shows cancer or a suspicion of cancer, nodules that grow large enough to interfere with swallowing or breathing, or nodules that cause cosmetic concern.
- Other methods: For nodules that produce excess hormone, medication or radioactive iodine; for selected benign nodules, needle-based shrinking techniques such as radiofrequency may be considered.
When should you see a doctor?
If you notice a new swelling in your neck, a rapidly growing lump, persistent hoarseness, or difficulty swallowing or breathing, it is advisable to see a doctor for assessment. If you have a known nodule, keeping to the recommended follow-up intervals allows any change to be detected early.
Frequently asked questions
Is every thyroid nodule cancer?
No. The great majority of nodules are benign; which nodules need further investigation is decided from the ultrasound findings and, if necessary, a biopsy.
Is a thyroid biopsy painful?
Fine-needle biopsy is similar to having blood drawn; it is brief, usually needs no anaesthetic and causes no more than mild discomfort.
Does a benign nodule need surgery?
Usually not. Benign nodules that cause no symptoms are monitored; surgery is considered when a nodule grows enough to press on surrounding structures or becomes suspicious.
This page is general information. Decisions about diagnosis and treatment are made for you personally, and only after an examination. If you have symptoms, see a doctor.