Thyroid nodules: when should you worry?

What is a nodule and how is it found?

A thyroid nodule is a mass inside the thyroid tissue that differs from the surrounding tissue and can vary in size. Nodules are most often found by chance – during a neck ultrasound – and most of them cause no complaints.

Statistically, 90–95% of detected nodules are benign. Still, every nodule deserves a careful approach: some can be malignant, and some can disturb the hormonal balance.

The most common misconception is: “My blood tests are normal, so there is no nodule.” On the contrary, many nodules develop without changing TSH, T3 and T4 levels. That is why an ultrasound is important alongside blood tests.

Which signs need attention?

In the following cases a nodule needs a “closer look” and further investigation:

• the nodule is growing quickly;
• swallowing or breathing has become difficult;
• the voice is hoarse or has changed;
• a hard, immobile lump can be felt in the neck;
• lymph nodes in the neck are enlarged;
• family members have had thyroid cancer;
• the ultrasound shows a suspicious image.

What do ultrasound and TIRADS show?

The size of a nodule alone is not a sign of danger. A large nodule can be completely harmless, while a very small one may need attention. For an endocrinologist, the ultrasound features of the nodule – its borders, internal structure and blood flow – matter more than its size.

Ultrasound features considered suspicious include: a hypoechoic structure, an irregular contour, microcalcifications, and a nodule that is taller than it is wide.

To describe these features in a common language, ultrasound reports often use the TIRADS classification. The nodule is scored by its features and assigned a risk category – the higher the category, the greater the suspicion.

If the report says TIRADS 4 or 5, it means the nodule looks suspicious and should be checked with a biopsy.

When is a biopsy (FNA) needed?

Finding a thyroid nodule does not always mean a biopsy is needed. The doctor decides based on the size of the nodule, its ultrasound appearance and any suspicious features. The main cases the doctor recommends:

• hypoechoic nodules larger than 1 cm;
• isoechoic nodules larger than 2 cm;
• a family history of thyroid cancer or elevated blood calcitonin – regardless of the nodule’s size;
• even if smaller than 1 cm, when two or more risk features are present: microcalcification, central blood flow, taller-than-wide shape, irregular borders, absent halo, enlarged nearby lymph nodes, firm structure on elastography.

How is FNA done, and is it frightening?

Fine-needle aspiration biopsy (FNA) is the standard method for evaluating thyroid nodules and has an accuracy above 90%. Only after FNA can one say with confidence whether a nodule is benign or malignant.

The procedure is performed under ultrasound guidance in sterile conditions and, in experienced hands, takes only 2–5 seconds. No anaesthesia or numbing is required, and patients usually feel no pain.

The belief that “a goitre must not be touched with a needle” has no scientific basis: a fine-needle procedure never spreads a nodule and does not cause cancer. If your doctor recommends a biopsy, it does not mean “you have cancer” – it is simply the most accurate and safe step to be fully certain at the cellular level.

The sample is sent for cytological examination. Based on the result, the doctor decides on monitoring, a repeat biopsy or treatment.

What if the nodule is benign?

A true nodule – one filled with cells – does not shrink on its own: it either stays the same size or grows. That is why, for small benign nodules, ultrasound and hormone tests are repeated every 6–12 months as your doctor advises.

If the nodule grows quickly, or you develop throat discomfort, difficulty swallowing or breathing, see a doctor without waiting for the next check-up. If a nodule has been found in your thyroid, don’t panic – but don’t become complacent either: regular monitoring and timely intervention when needed are the right way.