Thyroid Nodules

What are thyroid nodules?

Thyroid nodules are lumps that form within the thyroid gland, which is a butterfly-shaped organ that sits at the front of the neck and produces hormones that regulate metabolism. These nodules are quite common, especially in adults, and are often discovered during routine check-ups or imaging done for unrelated reasons. Many people may not even realise they have them, as most nodules do not cause symptoms.

Thyroid nodules can vary in size and structure. Some are very small and go unnoticed, while others can grow large enough to be felt or seen as a swelling in the neck. In certain cases, they may cause symptoms such as a visible lump, discomfort or obstruction when swallowing, or changes in voice. Rarely, a nodule may produce excess thyroid hormone, leading to symptoms of hyperthyroidism like rapid heartbeat or weight loss. But thyroid nodules can also be associated with normal or low thyroid function. 

Nodules are classified based on their number and content:

• Solitary nodule — a single distinct lump in the thyroid.

• Multiple nodules — more than one lump, often seen in a condition called multinodular goitre.

• Cystic nodules — filled with fluid, often benign.

• Solid nodules — made up of thyroid tissue, which may be benign or, in rare cases, cancerous.

Thorough evaluation by a specialist through physical examination, thyroid function tests, ultrasound imaging, and sometimes fine-needle aspiration (FNA) is essential to determine whether a nodule is harmless or requires further management.

What causes thyroid nodules? 

Thyroid nodules can develop for several reasons, most of which are non-cancerous. Understanding the underlying cause helps guide diagnosis and management. Common causes include:

• Thyroid cysts — fluid-filled sacs that typically form when overgrown tissue breaks down. These nodules are usually benign and may resolve on their own or remain stable over time.

• Colloid nodules — overgrowth of normal thyroid tissue that forms a lump within the gland. These are the most common type of nodule and are generally harmless.

• Thyroiditis (chronic inflammation) — autoimmune conditions like Hashimoto’s thyroiditis can cause the thyroid to swell, leading to nodule formation. These nodules may be linked with hypothyroidism/ Underactive thyroid.

• Multinodular goitre — an enlarged thyroid with multiple nodules This is the most common finding says Dr. Dinesh.

• Thyroid cancer — though most nodules are benign, a small percentage can be malignant. Cancerous nodules may grow rapidly, feel firm or fixed, or cause symptoms like hoarseness or difficulty swallowing.

Each case requires careful evaluation to determine whether a nodule is benign or potentially more serious.

What are the symptoms of thyroid nodules?

In many cases, thyroid nodules do not cause any symptoms and are discovered during a routine physical exam or imaging test done for another reason. However, when symptoms do occur, they may include:

• A visible lump or swelling in the neck — this is often the first noticeable sign, especially if the nodule is large or located at the front of the neck.

• Difficulty swallowing or a sensation of fullness in the throat — larger nodules can press against the esophagus or windpipe, making it uncomfortable to swallow or breathe.

• Hoarseness or voice changes — if a nodule presses on the vocal cords or nearby nerves, it can affect the voice.

• Neck pain or discomfort — though uncommon, some nodules may cause localised pain or a feeling of pressure in the neck.

• Signs of hyperthyroidism — if the nodule is overactive (called a “hot” nodule), it may produce excess thyroid hormone, leading to symptoms like:
  • Unexplained weight loss
  • Rapid heartbeat or palpitations
  • Nervousness or irritability
  • Increased sweating
  • Tremors
  • Difficulty sleeping

• Signs of hypothyroidism — in cases associated with autoimmune thyroiditis, the nodule may coincide with low thyroid hormone levels, causing:
  • Fatigue
  • Weight gain
  • Cold intolerance
  • Dry skin
  • Constipation

It’s important to remember that the presence of symptoms does not necessarily indicate cancer, and most thyroid nodules are benign. Proper evaluation through ultrasound and thyroid function tests helps determine the underlying cause.

Who is at risk of thyroid nodules in Singapore? 

Thyroid nodules are common, and certain individuals are more likely to develop them due to biological, environmental, and lifestyle-related factors. In Singapore, common risk factors include:

• Being female — women are 3 to 4 times more likely than men to develop thyroid nodules, largely due to hormonal influences.

• Age over 50 — the likelihood of developing nodules increases with age, especially in those above 50.

• Family history of thyroid conditions — having a close relative with thyroid nodules, goitre, or thyroid cancer raises your own risk.

• Iodine deficiency — a lack of iodine in the diet can lead to thyroid enlargement and nodule development, especially in areas where iodine supplementation is limited.This is rare in Singapore due to iodised salt. 

• Radiation exposure and genetics — a history of neck radiation (especially in childhood) or a family history of thyroid cancer increases the likelihood of developing concerning nodules.

• Chronic thyroiditis (e.g. Hashimoto’s disease) — autoimmune inflammation of the thyroid can lead to the development of nodules over time.

• Existing thyroid conditions — those with goitre or other benign thyroid disorders are more likely to develop additional nodules.

• Obesity and smoking — these lifestyle factors are linked to a higher risk of thyroid nodules and thyroid dysfunction.

How are thyroid nodules diagnosed? 

Thyroid nodules are often detected during a routine physical exam or incidentally on imaging studies done for unrelated reasons. Once a nodule is suspected, a step-by-step approach is used to determine its nature and whether further treatment is needed.

Common diagnostic steps include:

• Physical examination — a doctor may feel the front of your neck to check for any lumps, asymmetry, or enlargement of the thyroid gland.

• Thyroid function tests (blood tests) — these measure levels of thyroid hormones (T3, T4) and thyroid-stimulating hormone (TSH) to assess if the nodule is affecting hormone production.

• Ultrasound scan — this is the most important imaging test for thyroid nodules. It helps determine the size, number, structure (solid or cystic), and features that may suggest whether a nodule is benign or suspicious.

• Fine-needle aspiration (FNA) biopsy — if the ultrasound findings are suspicious or if the nodule is larger than a certain size (typically >1 cm with worrisome features), a thin needle is used to extract cells from the nodule for microscopic examination.

• Thyroid uptake scan (radioactive iodine uptake test) — this test may be done in specific cases to see if the nodule is “hot” (producing excess hormone) or “cold” (inactive). Hot nodules are rarely cancerous, while cold nodules may need closer evaluation. This is the most important test if someone has an overactive thyroid. 

• Molecular testing — in cases where biopsy results are indeterminate, genetic testing of the nodule tissue may be done to assess the risk of cancer.

Each step helps clarify whether the nodule is harmless and can be monitored, or if further treatment or surgery is needed.

What are the treatment options for thyroid nodules in Singapore? 

Treatment for thyroid nodules depends on several factors, including the size and type of the nodule, whether it’s causing symptoms, and whether it shows signs of cancer or affects thyroid hormone levels. In many cases, no immediate treatment is needed, and monitoring is sufficient.

Common treatment options include:

• Monitoring — if the nodule is small, benign, and not causing any symptoms, your doctor may recommend regular monitoring with ultrasound and thyroid function tests every 6–12 months.

• Radioactive iodine therapy — for overactive “hot” nodules that produce excess thyroid hormone, radioactive iodine may be used to shrink the nodule and reduce hormone production. This is a non-surgical option typically used in hyperfunctioning nodules.

• Minimally invasive procedures (e.g. radiofrequency ablation, ethanol ablation) — these image-guided techniques are increasingly used for benign but symptomatic nodules. They can reduce nodule size without the need for surgery, especially for patients who are not surgical candidates.

• Surgery (thyroid lobectomy or total thyroidectomy) — surgical removal may be recommended if:
  • The nodule is large and causing compressive symptoms
  • The nodule is 4cm or larger and therefore FNAC is not accurate
  • There is suspicion or confirmation of cancer
  • The biopsy result is indeterminate or repeatedly inconclusive
  • The patient prefers removal over ongoing monitoring

Each case is assessed individually, and the choice of treatment is made based on nodule characteristics, test results, and patient preference.

Summary 

Thyroid nodules are common growths within the thyroid gland that may be solid or fluid-filled, single or multiple, and are usually benign. While many nodules are found incidentally and cause no symptoms, others may lead to visible neck swelling, swallowing difficulty, or hormonal imbalances. 

Diagnosis typically involves a combination of physical examination, blood tests, ultrasound imaging, and fine-needle aspiration biopsy to determine whether the nodule is harmless or needs further attention. Treatment options range from simple monitoring to medication, radiofrequency ablation, or surgery, depending on the nodule’s size, function, and risk of malignancy. 

If you have noticed a lump in your neck, are experiencing related symptoms, or have concerns about thyroid health, schedule a consultation with us for detailed evaluation and personalised care.

Frequently Asked Questions (FAQs)