If you’ve felt a lump in your neck, or something getting in the way of you swallowing, it might turn out to be a thyroid nodule: a solid or fluid-filled lump that can form in your thyroid gland in your neck.
Thyroid nodules are very common, and aren’t usually harmful – lots of people don’t even realise when they have one. There are several different types, but in some cases they do cause symptoms and need treatment.
If you’re worrying about cancer because it’s a lump, this is unlikely – it’s estimated that about 85% to 96% of thyroid nodules are non-cancerous (benign).
Thyroid nodules are different from a swelling in your neck that can happen due to an enlarged thyroid gland, which is called a ‘goitre’.
So here’s what you need to know about who gets thyroid nodules and why they happen, as well as what treatments might be right for you.
Who is more likely to get a thyroid nodule?
Thyroid nodules are common, though estimates of prevalence vary. Some studies suggest that between 20% and 76% of the general population has at least 1 thyroid nodule.
Although anyone can get them, there are certain things that can make thyroid nodules more likely, including:
- being female – women are more likely to get them. One study found that 6.4% of women and 1.5% of men had visible thyroid nodules
- pregnancy – being pregnant causes an increase in growth factors such as hormones, which can trigger the growth of thyroid nodules
- being older – it’s estimated that about half of people aged 60 or over have a thyroid nodule that can either be felt or seen on imaging
- family history – having parents or siblings who’ve had thyroid nodules increases your chance of getting them
- being obese – several studies have shown obesity to be associated with thyroid nodules
- having fibroids – these are growths that can develop in and around the womb, and studies have found that people with fibroids have a higher risk of thyroid nodules. It’s thought that the hormone oestrogen may play a part
- radiation exposure – radiation to the head and neck from medical treatments (but not from screening procedures such as a CT scan) can increase your risk
Who is less likely to get a thyroid nodule?
Not having the risk factors above may make you less likely to get a thyroid nodule. Research shows that you may also have a decreased risk if you’re taking the contraceptive pill or medicines called statins, which are commonly prescribed to lower cholesterol.
Thyroid nodule symptoms
What symptoms you get will depend on the size and type of thyroid nodule you have – they can be single or multiple, hard or soft, and tender or not tender.
Often, you won’t even know you have a nodule, because you won’t feel it or have any symptoms, especially if it’s small.
If a nodule does cause symptoms, they can include:
- feeling or seeing a lump in your neck – nodules sometimes grow to a size where they can be felt or seen, often as a swelling at the bottom of your neck
- a choking feeling or difficulty swallowing – this can happen if a large nodule presses on your windpipe or food pipe
- symptoms of an overactive thyroid (hyperthyroidism) – occasionally, thyroid nodules make the thyroid hormone thyroxine. This extra thyroxine can lead to symptoms of an overactive thyroid, such as sweating, nervousness, shaking hands or body (tremor), weight loss and a fast heart rate
It’s also possible to have thyroid nodules and symptoms of an underactive thyroid (hypothyroidism), but this is less common.
What are the medical causes of thyroid nodules?
Conditions that can cause thyroid nodules to develop include:
- an overgrowth of normal thyroid tissue – it’s not clear why this happens, but the nodules this causes are called ‘adenomas’. They aren’t cancerous and don’t usually cause any problems unless they’re large, but they occasionally lead to an overactive thyroid
- long-term (chronic) inflammation of the thyroid gland – this can happen with thyroiditis, and can cause enlarged nodules. It’s often linked to an underactive thyroid
- a lack of iodine – iodine deficiency can cause thyroid nodules, but this is rare as iodine is routinely added to table salt and other foods
- cancer – thyroid cancer is rare, accounting for 1% of all new cancer cases in the UK, and it’s unlikely that a nodule is cancerous. Your risk increases if you have a family history of thyroid cancer or you’ve been exposed to radiation treatment in the past
What are the different types of thyroid nodules?
There are several types of thyroid nodule, including:
- colloid nodules – these are overgrowths of normal thyroid tissue. Although they may become large, they don’t spread outside the thyroid gland
- inflammatory nodules – these develop because of chronic inflammation and swelling of the thyroid gland. They can sometimes be uncomfortable
- thyroid cyst – these nodules are either full of fluid, or a combination of fluid and solid tissue
- multinodular goitre – a goitre is an enlarged thyroid gland, which can sometimes be made up of many nodules
- hyperfunctioning thyroid nodules – these types of nodules make thyroid hormone, so can cause symptoms of an overactive thyroid
- thyroid cancer – as mentioned above, this is rare, with the majority (85% to 96%) of thyroid nodules being non-cancerous
You might also hear your doctor talk about ‘hot’ and ‘cold’ nodules. Hot nodules make thyroid hormone. They show up on thyroid scans (see below), because they take up more of the radioactive isotope than normal thyroid tissue, and are almost always non-cancerous.
Nodules that take up less isotope are called cold nodules. In some cases, they can be cancerous, so more tests are needed.
When to see a doctor
Although most thyroid nodules don’t cause problems, you should always see a doctor if you notice a swelling in your neck. If you have trouble breathing or swallowing, it’s even more important.
Thyroid nodules need seeing by your doctor to rule out the unlikely possibility of cancer.
You should also get medical advice if you have symptoms of an overactive thyroid, such as:
- sudden weight loss – even though your appetite is normal or has increased
- a fast or pounding heartbeat
- trouble sleeping (insomnia)
- muscle weakness
- nervousness or irritability
Likewise, you should see your doctor if you notice symptoms of an underactive thyroid, such as:
- feeling cold or very tired
- dry skin
- memory problems
- low mood or depression
- trouble pooing (constipation)
How thyroid nodules are diagnosed
If you go to the doctor because you can feel a lump, they’ll give you a physical examination. You’ll be asked to swallow while they examine your neck, because a nodule in your thyroid gland will usually move up and down when you do this.
They’ll also check you for any signs of an underactive or overactive thyroid gland.
In some cases, nodules may also be found if you’re having tests for a different condition.
If they find a nodule, your doctor will arrange some tests to get more information and rule out the possibility of cancer. These can include:
- thyroid function tests – these are blood tests that measure your levels of thyroid hormones, to see if your thyroid gland is working normally
- ultrasound scan – this painless test is very important for checking thyroid nodules. It uses high-frequency sound waves to get an accurate picture of your thyroid gland and shows the size of a nodule, and if it’s filled with fluid. It can also show nodules too small to be felt, and give an indication about whether a nodule may be cancerous
- fine-needle aspiration biopsy (FNA) – this is a simple test where a doctor uses a very thin needle to take samples from the nodule to check for abnormal cells (such as cancer)
- thyroid scan – with this test, radioactive iodine is injected into a vein in your arm and a special camera takes pictures of your thyroid to help see what type of nodule you have. Because ultrasound and biopsy are so accurate, it isn’t usually used to diagnose nodules, unless they’re causing overactive thyroid. In these cases, a thyroid scan may suggest no other tests are needed
Thyroid nodule treatment
The treatment of thyroid nodules depends on the type you have. Most kinds of nodules will involve 1 or more of the following treatments:
- ‘watchful waiting’ – this is when the nodule doesn’t need treatment, but it’s monitored with an ultrasound scan every 6 to 12 months and a yearly examination by your doctor. You may have another biopsy if your nodule gets bigger. If your nodule doesn’t change, you may never need treatment
- thyroid hormone treatment – if you have an underactive thyroid, you may need a daily supplement of thyroid hormone. Read more about underactive thyroid treatment
- surgery – if you have a large nodule that’s making it difficult for you to swallow or breathe, a large multinodular goitre, or a nodule that gets larger or looks like it might have a cancer risk, surgery may be recommended. Most thyroid nodules that are cancerous will be removed by a surgeon. Read more about thyroid cancer treatment
If you have thyroid nodules that are making excess thyroid hormone, your doctor may recommend overactive thyroid treatments, such as:
- medication – medicines called thionamides can stop your thyroid making excess hormones
- radioactive iodine – this radiotherapy treatment destroys cells in your thyroid gland to reduce the amount of hormones it makes
- surgery – if other treatments aren’t suitable or don’t work, you may need surgery to remove part or all of your thyroid gland
Your health questions answered
What are the risks of thyroid surgery?
Answered by: Dr Roger Henderson
“Every operation carries risks, no matter how simple or complicated it is, and thyroid surgery is no exception. It’s usually very safe, with the risk of complications estimated to be between 1% and 2%. Your surgeon will discuss the risks with you beforehand, but the main possible complications are infection, nerve damage that could affect your voice or breathing, and damage to your parathyroid glands, which are near your thyroid gland.”