Thyroid Nodule and Goitre — Ankara

What is a thyroid nodule, and how common is it?

The thyroid is a butterfly-shaped gland at the front of the neck, just below the larynx. Rounded lesions within it are called nodules. Enlargement of the gland as a whole is called a goitre; a goitre may or may not contain nodules.

Nodules are common. On palpation they are found in roughly 5% of adults, but on ultrasound the reported prevalence ranges from about 20% to 76% depending on the population and method. The more sensitive the imaging, the more nodules are found.

That has a practical consequence: finding a nodule is not in itself a reason for alarm. Around 5% of nodules are malignant, with series reporting 4% to 6.5%. The purpose of assessment is to identify that small minority without over-treating the rest.

Which symptoms point to the thyroid?

Most nodules cause no symptoms and are found incidentally on imaging done for another reason. Where symptoms exist they usually fall into two groups: pressure effects, or effects of altered hormone levels.

• Swelling or fullness in the neck — typically moving up and down on swallowing
• Difficulty swallowing or a sense of catching — pressure on the oesophagus from a large nodule
• Shortness of breath, worse lying flat — pressure on the windpipe
• Hoarseness — particularly if persistent, needs separate assessment
• Signs of excess hormone — palpitations, sweating, weight loss, heat intolerance, tremor
• Signs of low hormone — fatigue, feeling cold, constipation, weight gain, dry skin

None of these on its own indicates malignancy; all occur with benign enlargement too. Even so, pressure symptoms and persistent hoarseness warrant assessment regardless of nodule size.

How is it assessed?

Thyroid assessment has three parts and the order matters: hormone status first, then ultrasound, then biopsy where indicated.

• Blood tests (TSH, and free T4/T3 where needed) — show whether the gland is under- or over-active. A low TSH may mean the nodule is producing excess hormone, which changes the approach and brings a scintigraphy scan into consideration.
• Neck ultrasound — shows size and structure: solid or cystic, margin regularity, microcalcification, whether the nodule is taller than wide, and the appearance of nearby lymph nodes.
• Fine-needle aspiration (FNA) — a cell sample taken with a thin needle under ultrasound guidance. It is not an operation and does not need general anaesthesia.

Ultrasound features place the nodule in a risk group, and the biopsy decision follows from that group. In the American Thyroid Association's 2015 guideline the thresholds are 1 cm for high and intermediate suspicion, 1.5 cm for low suspicion and 2 cm for very low suspicion. The decision therefore rests on size and sonographic appearance together, not size alone.

What does the biopsy result mean?

Results are reported using an internationally accepted system (Bethesda). The answer is not simply benign or malignant; there are indeterminate categories in between, and these are managed differently.

A benign nodule is usually not operated on but followed with ultrasound at set intervals. Indeterminate results may lead to a repeat biopsy, molecular testing or diagnostic surgery. A malignant result is planned together with endocrinology and surgery.

In some situations surgery is considered regardless of the cytology: pressure effects, extension into the chest, or an overactive nodule that cannot be controlled with medication.

Why does follow-up matter?

A benign nodule can still grow or change its sonographic appearance over time. A benign biopsy does not mean the nodule never needs looking at again.

The follow-up interval depends on the ultrasound appearance and the initial result. Stable low-risk nodules are checked less often; higher-risk appearances need closer follow-up.

A new, rapidly growing, hard or fixed swelling in the neck should be assessed without waiting for the next scheduled interval.