What are thyroid nodules?

The thyroid is a butterfly-shaped organ located on the front of your neck, just under the Adam’s apple. The thyroid is responsible for producing hormones that regulate functions in our body, such as heart functions, digestion and body temperature. Sometimes, normal thyroid tissue grow, causing an unusual lump or thyroid nodules to form in the thyroid gland.

Thyroid nodules tend to occur more in women; they are detected in 1 to 2 percent of men and 6 percent of women. They also occur 10 times more often in older individuals and are usually not diagnosed.

What causes a thyroid nodule to form?

When the thyroid overgrows, it can cause one or more thyroid nodules to form. Thus far, we do not know yet why this happens, but it could most commonly be caused by overgrowth of fluid-filled cysts, inflammation or mere thyroid tissue. Nevertheless, when nodules occur, cancer is the biggest concern. Fortunately, cancer cases are rare, uncommon and found in less than 5 per cent of all nodules.

In essence, whenever a thyroid nodule is discovered, the possibility of cancer must always be taken into consideration.

Above: a 4cm thyroid cyst in a young female patient

Who is at risk of developing thyroid nodules?

Family history
Individuals with a family history of thyroid nodules or other endocrine cancers are more susceptible to developing this condition.

A lack of iodine, an essential mineral needed to make thyroid hormone, can put you at risk of developing thyroid nodules. Iodine is commonly found in seafood.

Older individuals are at higher risk of developing thyroid nodules.

Women are more likely to develop thyroid nodules compared to men.

Radiation exposure
Radiation exposure received to the head and neck from medical treatments (excluding diagnostic procedures such as CT scans) increases your risk of developing thyroid nodules.

Are there different types of thyroid nodules?

There are a few types of thyroid nodules, including:

Colloid nodules
Colloid nodules are overgrowths of normal thyroid tissue and are not cancerous. They may be multiple or large but do not spread beyond the thyroid gland.

Thyroid cysts
Thyroid cysts are classified as simple cystic (contain only fluid) or complex (contain both fluid and solid components). Thyroid cysts can vary in size, often growing to large sizes. Acute cysts can also be quite painful. Simple cysts generally have a very low malignant risk. Complex cysts, on the other hand, may harbour malignancy and may need to be surgically removed.

Inflammatory nodules
Inflammatory nodules are caused by generalized chronic swelling of the thyroid gland and may be painful.

Multinodular goiter
A goiter simply means an enlarged thyroid gland. It may be simple where the whole gland is enlarged or multinodular where there are multiple nodules. It can occur where there is a lack of dietary iodine (endemic goiter) or resulting from excess thyroid stimulating hormone from the pituitary gland in the brain. Multinodular goiters can be a toxic multinodular goiter (produces excess thyroxine) or non-toxic in which the thyroid function is normal.

Hyperfunctioning thyroid nodules
Hyperfunctioning thyroid nodules basically produce an excess of thyroid hormones, which lead to the development of hyperthyroidism. Hyperthyroidism can lead to heart problems like high blood pressure, sudden cardiac arrest, abnormal heart rhythm and other health conditions

Thyroid cancer
Thyroid cancer arises from the presence of malignant cells within a nodule. It arises de novo in most cases but can also undergo transformation from a long-standing multinodular goiter.

How do I know if I have thyroid nodules?

Many patients with thyroid nodules do not have symptoms and their condition is usually diagnosed by chance. However, these patients usually have noticeable large lumps in the front portion of their necks together with some of these symptoms:

  • Discomfort or difficulty with swallowing or breathing
  • Voice change or hoarseness
  • Pain in the neck
  • Goiter
Thyroid Nodules
Above: Multinodular goitre
Thyroid Nodules
Above: multinodular goitre with an extention into the chest

In addition, thyroid nodules may be associated with imbalance of thyroid hormone levels, so you might want to watch out for symptoms of hypothyroidism or hyperthyroidism. Symptoms of hypothyroidism include:

  • Constant fatigue
  • Heavy menstrual flow
  • Always feeling cold
  • Dry and coarse skin and hair
  • Hair loss
  • Weakness and irritability
  • Depressed moods

Symptoms of hyperthyroidism include:

  • Persistent weight loss
  • Hypermetabolism such as increased heart rate, increased sweating and somnolence
  • Hair loss

What tests are needed for thyroid nodules in Singapore?

Fine Needle Biopsy
A fine needle biopsy is a simple yet efficient procedure that provides doctors with most information they need more than 85 percent of the time. This includes a treatment decision for the patient. This biopsy requires you to lie down as still as possible with your head tipped backwards. The procedure will be performed under a ultrasound guidance to ensure accurate placement of the fine needle within the thyroid gland nodule.

The use of fine needle biopsy has expedited the diagnosis of thyroid nodules as well as reduced the need for unnecessary operations.

Thyroid Scan
A thyroid scan is able to tell if a nodule is hyperfunctioning. This procedure involves injecting or swallowing a small dose of radioactive isotope and taking a picture of the thyroid gland. However, it should not be performed on pregnant or breastfeeding women.

In a thyroid ultrasound, nodules as small as 2 millimeters are detected through the use of high frequency sound waves that pass through the skin. This procedure can also distinguish fluid-filled nodules from solid nodules, as well as cancerous nodules.

How are thyroid nodules treated in Singapore?

If the thyroid nodules are proven benign, they can be monitored regularly through the use of ultrasound.

If the thyroid nodules are symptomatic, suspicious for cancer or proven to be cancerous, thyroid surgery may be recommended.


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