Thyroid nodules: causes, tests and treatment

The thyroid sits at the front of the neck. Sometimes part of it forms a distinct lump. The British Thyroid Foundation describes nodules as lumps in the gland and says most are harmless. One nodule is called solitary, and several together make a multinodular goitre.

The NHS notes that a goitre may feel smooth or lumpy and that the swelling is sometimes only on one side. It usually appears at the lower front of the neck and is typically painless.

The BTF separates solitary nodules, multiple nodules, diffuse goitre and retrosternal goitre. A solitary nodule is most commonly benign and often can be left untreated, but surgery is usually recommended if cancer cannot be excluded. A hot nodule that makes too much hormone can be treated with drugs, radioactive iodine or sometimes surgery.

A multinodular goitre is common and usually does not need an operation, unless there are swallowing or breathing problems, it grows rapidly, one nodule is a concern, or it is unsightly. A diffuse goitre is often caused by autoimmune conditions such as Hashimoto's thyroiditis or Graves' disease. A retrosternal goitre grows down behind the breastbone and can squash the windpipe, gullet or neck veins, and surgery may be considered.

Many nodules cause no symptoms. A visible or palpable lump at the front of the neck is the commonest sign. The NHS lists other possible symptoms of a goitre: a cough that does not go away, a hoarse voice or voice changes, a feeling of something stuck in the throat, wheezing, and difficulty swallowing or breathing.

If a nodule makes extra thyroid hormone you may notice overactive thyroid symptoms such as palpitations, weight loss, sweating or tremor. If swelling comes with an underactive gland, tiredness and feeling cold may appear instead.

The BTF says the main cause of thyroid nodules and enlargement is unknown. They are more common in women, increase with age and often appear in pregnancy. The NHS lists causes of a swollen thyroid including an overactive or underactive gland, harmless lumps, hormone changes in puberty, pregnancy or menopause, thyroiditis, Graves' disease, too little iodine in the diet (rare in the UK) and thyroid cancer (rare).

Thyroid problems often run in families. If relatives have thyroid disease, it is worth mentioning when you see your GP.

The BTF lists the usual tests. A blood test is usually first, to check that the thyroid is not over- or underactive. An ultrasound scan is painless, shows the number and size of nodules and gives information on the likelihood that one is benign or cancerous. Fine needle aspiration cytology removes cells from a nodule with a thin needle for examination under a microscope. There may be some discomfort, but it is usually quick.

A CT scan may be used to check the position of a retrosternal goitre relative to the windpipe and gullet. A nuclear medicine scan checks the size, shape and position of the thyroid and shows over-active (hot) or under-active (cold) areas. The NHS lists blood tests, an ultrasound scan and a biopsy with a small needle as the usual tests for a goitre.

Treatment depends on the type. The BTF lists thyroid surgery, radioactive iodine, antithyroid drugs and levothyroxine tablets. Many benign nodules need only monitoring. The NHS says most goitres are small and do not cause problems, and that those caused by an underactive or overactive thyroid can usually be treated with medicines.

Surgery is considered if cancer cannot be excluded, if a goitre is making breathing and swallowing difficult, or for large or rapidly growing swellings. A few UK centres use ethanol injection for cysts to avoid surgery, according to the BTF. After surgery to remove most or all of the thyroid, levothyroxine replaces the missing hormone, and for thyroid cancer is given in a slightly higher dose to help prevent recurrence.

The BTF summarises that most nodules and swellings are not cancerous and most thyroid cancers are curable. Benign nodules are often followed with repeat ultrasound and blood tests, and may stay unchanged for years.

If you have surgery, regular thyroid blood tests are needed afterwards. A nodule found incidentally still deserves a proper assessment so that the small number needing treatment are not missed.

See a GP if you notice a lump or swelling at the front of your neck, as the NHS and the BTF both advise. A rapidly growing lump, a hoarse voice that lasts, or difficulty swallowing should be reviewed without delay.

Call 999 or go to A&E if you find it hard to breathe or have a wheezing noise when you breathe. The NHS says not to drive yourself in this situation.

On the NHS, the GP arranges blood tests and refers to a specialist clinic if needed, where ultrasound and a needle test can often be combined. Urgent referral pathways exist for suspected cancer.

Some people choose private ultrasound and endocrine or head and neck assessment for speed. Ask for the ultrasound report, any needle test result, and a plan for follow-up scans, so care can continue smoothly if you return to the NHS.