Goitre and thyroid nodules

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Thyroid enlargement spans physiological variation, autoimmune diffuse disease, multinodular hyperplasia, cysts, inflammatory lesions and neoplasia. A visible neck swelling may be clinically harmless, while a small posterior or substernal lesion can affect the recurrent laryngeal nerve or airway. History and examination therefore prioritise progression, compression and local invasion before cosmetic dimensions.

Ultrasound is the main structural risk tool when a nodule or gland abnormality has been appropriately identified. Composition, echogenicity, shape, margin, calcification, extrathyroidal extension and lymph-node appearance contribute to a standardised category. Vascularity alone is a weak malignancy discriminator. The 2026 UK consensus emphasises context-sensitive thresholds and multidisciplinary review rather than one rigid size rule applied to every U3, U4 or U5 lesion.

Function changes the diagnostic route. Low TSH prompts free hormones and scintigraphy through endocrine or nuclear medicine, because a hot focus rarely needs aspiration. Normal or high TSH leaves ultrasound-led risk stratification central. Cytology is reported in a Thy category and must be reconciled with clinical and sonographic risk; discordant or repeatedly non-diagnostic cases belong in a thyroid multidisciplinary team rather than a cycle of unplanned procedures.

Key points

Goitre means thyroid enlargement and can be diffuse or nodular, euthyroid, hypothyroid or hyperthyroid; structure and function must be assessed separately.
Most thyroid nodules are benign, but history, examination and structured ultrasound determine which need cytology or specialist surveillance.
Ask about growth rate, pain, dysphagia, dyspnoea, positional symptoms, voice change, radiation exposure, family syndromes and previous thyroid disease.
Examine size, consistency, mobility, retrosternal signs, tracheal position, cervical nodes and voice; stridor or Pemberton-type congestion requires urgent escalation.
Measure TSH before or alongside ultrasound because a suppressed result directs functional scintigraphy and changes whether a nodule should be aspirated.
Ultrasound should report both lobes, nodule size and features, cervical nodes and a recognised local risk category, not simply describe a nodule as present.
Fine-needle aspiration is the first pathological test for an indicated nodule; size thresholds depend on ultrasound risk, clinical context and current local multidisciplinary guidance.
A scintigraphically hot autonomous nodule is rarely malignant and generally does not need routine FNA unless a separate suspicious feature exists.
CT of neck and chest helps define retrosternal extension or tracheal compression, but iodinated contrast requires thought when hyperthyroidism or radioiodine treatment is relevant.
Normal TSH does not rule out thyroid cancer, and abnormal TSH does not prove a nodule is malignant; avoid collapsing two different questions into one.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Diffuse autoimmune enlargement

Graves disease or autoimmune thyroiditis can enlarge the whole gland through receptor stimulation, inflammation or compensatory tissue change.

Nodular hyperplasia and cysts

Clonal nodular growth, colloid accumulation and cystic degeneration commonly produce solitary or multinodular structural abnormalities, often with normal thyroid function.

Inflammatory or malignant disease

Thyroiditis and thyroid neoplasia can present as focal or diffuse enlargement, particularly when pain, rapid growth, fixation or cervical nodes accompany the swelling.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Thyroid tissue enlarges
Hyperplasia, inflammation, fluid accumulation or neoplastic growth increases gland volume and may create a palpable or imaging-detected nodule.
2
Function may become independent
Some nodules produce thyroid hormone autonomously and suppress TSH, while many structural lesions remain non-functioning and biochemically silent.
3
Local structures may be compressed
Posterior, invasive or substernal growth can affect trachea, oesophagus, recurrent laryngeal nerve or cervical vessels despite modest visible enlargement.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Benign-leaning presentation

A longstanding soft mobile nodule or symmetric goitre without growth, nodes, voice change or compression is lower risk, but still requires appropriate TSH and structural triage rather than visual reassurance alone.

Cancer concernRed flag

Rapid or progressive growth, hard fixation, suspicious cervical nodes, persistent unexplained hoarseness, prior neck irradiation or a relevant familial syndrome should accelerate specialist and cancer-pathway assessment.

Airway or mediastinal compressionRed flag

Stridor, orthopnoea, positional dyspnoea, dysphagia, facial plethora or venous distension on arm elevation suggests tracheal, oesophageal or thoracic inlet compromise and may require emergency care.

Acute painful expansionRed flag

Sudden pain and enlargement may represent haemorrhage into a cyst or nodule, while fever and focal inflammatory signs raise abscess; airway effect determines urgency.

Autonomous functional nodule

Suppressed TSH, palpitations and a focal hot area on scintigraphy define autonomy; examine for other nodules because structural risk may lie outside the functioning focus.

Inflammatory or autoimmune goitre

A diffuse firm gland can accompany autoimmune thyroiditis, whereas a smooth vascular goitre with bruit supports Graves; biochemical and antibody context refines the structural impression.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
TSH with reflex free thyroid hormonesFirst step
Why
Determine whether the structural lesion is euthyroid, hypoactive or autonomous.
Interpretation and limitations
Low TSH prompts free T4, free T3 and functional scintigraphy consideration; high TSH with low free T4 suggests gland failure but does not classify cancer risk.
02
High-quality thyroid and cervical-node ultrasound
Why
Risk-stratify nodules and identify nodal or extrathyroidal disease.
Interpretation and limitations
The report should document dimensions, composition, echogenicity, margins, shape, calcification, extension, both lobes and central and lateral nodes using the local U or validated system.
03
Technetium thyroid scintigraphy
Why
Identify autonomous function when TSH is suppressed.
Interpretation and limitations
A hot nodule with suppressed background tissue is unlikely malignant and usually avoids FNA; cold or indeterminate regions remain subject to ultrasound risk assessment.
04
Ultrasound-guided fine-needle aspiration cytology
Why
Obtain cells from nodules meeting clinical and sonographic criteria.
Interpretation and limitations
Interpret Thy category with ultrasound and history. Non-diagnostic, indeterminate or discordant results require repeat sampling, molecular or surgical consideration through the local MDT.
05
CT neck and thorax
Why
Map retrosternal extent, tracheal calibre and relationship to mediastinal structures.
Interpretation and limitations
Compression or marked deviation supports ENT or endocrine-surgical planning; discuss whether iodinated contrast is necessary when autonomy or future radioiodine matters.
06
Flexible nasendoscopy or vocal-cord assessment
Why
Investigate persistent voice change and document recurrent-laryngeal function before surgery.
Interpretation and limitations
Vocal-cord paresis with a thyroid mass is concerning for invasive malignancy and needs expedited head-and-neck or thyroid MDT management.
07
Calcitonin in selected specialist contexts
Why
Evaluate possible medullary thyroid cancer where history, ultrasound or local policy supports testing.
Interpretation and limitations
Do not use indiscriminately without understanding assay and false-positive influences; an elevated result requires specialist confirmation and MEN2-oriented assessment.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Cervical lymphadenopathy

A lateral neck lump separate from the gland may be nodal disease from infection or malignancy; ultrasound defines its relationship and morphology.

Thyroglossal or other neck cyst

A midline cystic lesion may move with swallowing or tongue protrusion but does not share the thyroid's biochemical or ultrasound pattern.

Subacute thyroiditis

A tender painful gland with raised inflammatory markers and transient hormone release favours inflammatory enlargement rather than an asymptomatic nodule.

Thyroid cancer

Rapid growth, fixation, hoarseness, suspicious ultrasound features or abnormal nodes increase concern and direct cytology through the specialist pathway.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Airway firstManage compressive neck diseaseFirst stepStridor, rapid expansion, positional respiratory compromise or venous congestion is present.

1Keep the patient in the safest tolerated position, assess ABCDE and summon senior anaesthesia and ENT before airway deterioration makes intervention more difficult.
2Use urgent cross-sectional imaging only when the airway is sufficiently stable, with endoscopic assessment and critical-care monitoring directed by the specialist team.
3DefinitivePlan definitive decompression, drainage or thyroid surgery according to cause; do not send a threatened airway through a routine outpatient ultrasound route.

02New noduleRisk-stratify structure systematicallyA palpable or appropriately triaged incidental thyroid nodule is identified.

1Document growth, compression, voice, irradiation and familial risk, examine thyroid and nodes, and obtain TSH before or with a structured ultrasound request.
2Use the local ultrasound risk category and size plus clinical features to decide discharge, surveillance, FNA or direct cancer-pathway referral.
3Ensure the patient receives the result and next interval explicitly; incidental low-risk nodules should not generate indefinite unowned imaging.

03Low TSH noduleEstablish function before cytologyA patient with a nodule has suppressed TSH.

1Measure free T4 and free T3, assess cardiovascular stability and review Graves signs, iodine exposure, amiodarone and pregnancy status.
2Arrange endocrine-directed scintigraphy when safe; a confirmed hot nodule generally proceeds to autonomy treatment rather than routine aspiration.
3Still review the whole ultrasound for a separate suspicious cold lesion or node, and route any discordant concern through the thyroid MDT.

04Cytology resultReconcile pathology with imagingFine-needle aspiration returns a Thy classification.

1Match the sampled site and Thy category to ultrasound risk, size, growth, nodes and clinical concern rather than reading cytology in isolation.
2Discharge or surveil benign concordant disease according to local guidance, and refer indeterminate or malignant categories to the thyroid cancer multidisciplinary team.
3For repeated non-diagnostic or clinically discordant samples, let the MDT choose repeat FNA, core biopsy in selected cases or diagnostic surgery.

Key medicines and prescribing safety1 treatment · regimens, roles and cautions

Replaces absent thyroid hormone after definitive surgery or radioiodine when hypothyroidism results.

Levothyroxine after definitive hypothyroid treatment

Use an individual once-daily replacement regimen after total thyroidectomy or ablative treatment, selected by age, weight, pregnancy and cardiac risk and titrated against the appropriate TSH target.

Do not prescribe TSH-suppressive doses for an ordinary benign nodule. Cancer-specific suppression targets belong to specialist oncology follow-up and require rhythm and bone-risk review.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Airway or swallowing compromise

Large, retrosternal or invasive disease can compress trachea or oesophagus, causing breathlessness, stridor, dysphagia or positional symptoms.

Recurrent laryngeal nerve dysfunction

Posterior or malignant extension may impair vocal-cord movement, producing persistent hoarseness, ineffective cough and aspiration risk that requires prompt structural assessment.

Thyrotoxicosis

Autonomous nodules can produce persistent thyroid hormone excess, increasing atrial fibrillation, heart failure and bone-loss risk.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

For ultrasound surveillance, use the interval and stopping rule linked to the local risk category, size and clinical context rather than repeating scans annually by default.
Advise earlier review for growth, hardening, new node, persistent voice change, dysphagia, dyspnoea or pain, even when a previous sample was benign.
Track thyroid function separately from nodule dimensions, particularly after radioiodine, hemithyroidectomy or when autoimmune disease coexists.
After FNA, ensure cytology, ultrasound and clinical findings are reconciled and communicated; discordance should be visible on the MDT agenda.
Following thyroid surgery, monitor voice, wound, calcium symptoms and pathology, then establish the appropriate levothyroxine and cancer-surveillance plan.
For substernal goitre managed conservatively, document respiratory and swallowing symptoms and define what change triggers repeat imaging or surgical reconsideration.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Function and cancer are different axes

TSH and scintigraphy describe hormone activity; ultrasound and cytology describe structural malignancy risk. One result cannot substitute automatically for the other.

A small lesion can matter

Location beside the recurrent laryngeal nerve, trachea or thoracic inlet can make modest size clinically important, while a large superficial goitre may be asymptomatic.

Ultrasound needs a question

Scanning nonspecific symptoms without a palpable or appropriately triaged structural indication finds incidental nodules and can create procedures without improving outcomes.

Vascularity is weak alone

Colour flow can support functional impressions but is not a reliable standalone cancer discriminator; morphology and nodes carry more structured risk information.

Concordance protects patients

Benign cytology is reassuring when it matches a low-risk lesion sampled correctly; a highly suspicious ultrasound with benign cells deserves multidisciplinary review, not automatic discharge.

11Common pitfallsFrequent interpretation and management errors.

01
Assuming a normal TSH proves a thyroid nodule is benign.
02
Sending a patient with stridor for routine outpatient imaging instead of airway escalation.
03
Requesting FNA before scintigraphy in a suppressed-TSH autonomous nodule pathway.
04
Applying a single size cutoff without ultrasound category, clinical risk or local consensus.
05
Calling repeated non-diagnostic cytology reassuring because no malignant cells were seen.
06
Using vascularity alone to label a lesion malignant or benign.
07
Forgetting iodinated contrast implications before planned radioiodine or in active autonomy.
08
Losing ownership of an incidental nodule between radiology, primary care and the MDT.