Thyroid Nodules and Goitre: When a Lump in the Neck Needs Testing
A lump in the front of the neck causes understandable alarm. The reassuring reality is that thyroid nodules are extremely common, found in a large proportion of adults when the neck is scanned, and the great majority are benign. The purpose of investigation is to identify the small minority that are not, without over-treating the rest.
Definitions
A goitre is simply an enlarged thyroid gland. It may be diffuse, meaning uniformly enlarged, or nodular.
A nodule is a discrete lump within the gland. Nodules may be solitary or multiple, solid, cystic or mixed.
Neither term says anything about whether the gland is working normally or whether the lump is cancerous. Those are separate questions answered by separate tests.
How they are found
- As a visible swelling that moves up when swallowing, which is the classic sign of thyroid origin
- As a lump felt by the patient or by a doctor
- Incidentally on a neck ultrasound, CT or carotid Doppler done for another reason, which is now the commonest route
Symptoms worth noting
Most nodules cause nothing at all. Report any of these:
- Rapid growth over weeks
- A hard, fixed lump that does not move on swallowing
- Hoarseness or voice change, suggesting involvement of the nerve to the voice box
- Difficulty swallowing or a persistent sensation of something stuck
- Difficulty breathing, or breathlessness on lying flat, suggesting tracheal compression
- Enlarged neck lymph nodes
- Pain, which is more often inflammatory than malignant
Symptoms of thyroid overactivity, meaning weight loss, palpitations, tremor, heat intolerance, anxiety and loose stools, suggest a functioning or toxic nodule. Symptoms of underactivity suggest associated autoimmune thyroiditis.
Features that raise concern
- Age under 20 or over 60
- Male sex
- Previous radiation exposure to the head or neck, especially in childhood
- Family history of thyroid cancer, or of syndromes such as MEN2
- A single hard, fixed nodule
- Associated lymph node enlargement
- Hoarseness
Investigation
Thyroid function tests. TSH first. A suppressed TSH suggests a functioning nodule, which is almost never cancerous, and is followed by a radionuclide scan rather than a biopsy.
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Ultrasound. The central investigation. It measures size, counts nodules and assesses features. Reporting systems such as TI-RADS grade risk based on composition, echogenicity, shape, margin and the presence of microcalcifications. A taller-than-wide shape, irregular margins, marked hypoechogenicity and microcalcifications are the suspicious features. Lymph nodes are assessed at the same time.
Fine needle aspiration cytology. A thin needle sample taken under ultrasound guidance, usually without anaesthesia, taking a few minutes. It is the definitive test for whether a nodule is benign. Results are reported using the Bethesda system, from non-diagnostic through benign, indeterminate categories, suspicious, and malignant.
Not every nodule needs a biopsy. The decision depends on size combined with ultrasound features: a small nodule with entirely benign appearances may simply be watched, while a smaller nodule with suspicious features is sampled.
Not useful routinely: thyroid antibodies for cancer risk, thyroglobulin as a screening test, and CT or MRI unless the goitre extends behind the breastbone or compression is suspected.
Treatment
Benign, small, asymptomatic nodules are monitored with periodic ultrasound, not removed.
Large or compressive goitres are treated surgically, or sometimes with radioactive iodine for a toxic nodular goitre.
Toxic nodules, which cause hyperthyroidism, are treated with antithyroid drugs, radioactive iodine or surgery.
Cystic nodules may be aspirated for symptom relief, though they often refill.
Thyroid cancer is treated surgically, often with radioactive iodine afterwards and lifelong thyroid hormone. The common types, papillary and follicular, have excellent long-term survival when treated, which is worth saying plainly because the word cancer here carries a very different prognosis from most others.
Thermal ablation techniques are emerging for benign symptomatic nodules in some centres.
Iodine
Adequate iodine intake prevents the deficiency goitre that was historically common across the Gangetic plain and sub-Himalayan belt. Iodised salt is the practical measure. More iodine is not better: excess intake can trigger both over and underactivity, so iodine supplements and kelp preparations should not be taken without a reason.
Follow-up
Benign nodules are usually rechecked by ultrasound at intervals of 12 to 24 months initially, lengthening if stable. Report any rapid growth, voice change or new neck lumps between appointments rather than waiting.
This is general information. A neck lump should be assessed by a doctor; do not rely on reassurance from an article or from how it feels.