Should a patient with an enlarged thyroid be referred for a neck ultrasound?

Yes, Send for Ultrasound Immediately

Any patient with an enlarged thyroid (goiter) should undergo high-resolution neck ultrasound as the initial imaging study to characterize the gland, identify discrete nodules, assess for suspicious features, and evaluate cervical lymph nodes. 1, 2

Why Ultrasound Is Essential

Ultrasound is the only appropriate first-line imaging modality for thyroid evaluation, providing superior resolution compared to CT or MRI for distinguishing benign from malignant pathology 1. The American College of Radiology explicitly recommends ultrasound for any palpable thyroid abnormality, including diffuse enlargement 1.

Key advantages of ultrasound include:

• Detects occult nodules: Up to 50% of adults harbor thyroid nodules on ultrasound that are not palpable, and 5-15% of these are malignant 2, 3
• Characterizes suspicious features: Identifies microcalcifications (93.6% specificity for papillary carcinoma), irregular margins, marked hypoechogenicity, and abnormal vascularity 4, 5
• Evaluates lymph nodes: Assesses central (level VI) and lateral neck (levels II-V) compartments for metastatic disease, which occurs in approximately 50% of medullary thyroid carcinoma cases at presentation 1
• Guides intervention: Determines which nodules require fine-needle aspiration based on size and risk stratification 2, 5

What to Order Specifically

Request "bilateral thyroid ultrasound with evaluation of thyroid and central neck (level VI)" to ensure comprehensive assessment 5. If the goiter is large, symptomatic, or associated with palpable lymphadenopathy, add "with lateral neck ultrasound (levels II-V)" 5.

The ultrasound report should document:

• Gland dimensions and echogenicity (diffuse vs. nodular enlargement) 1
• Presence of discrete nodules ≥5 mm with size, composition (solid vs. cystic), echogenicity, margins, calcifications, and vascularity 2, 5
• Cervical lymph nodes with assessment for size, shape, loss of fatty hilum, cystic changes, microcalcifications, and abnormal blood flow 1, 5
• Substernal extension if the goiter is large or causes compressive symptoms 1

Clinical Context That Modifies Urgency

Expedite ultrasound (within days) if:

• Compressive symptoms are present—dysphagia, dyspnea, orthopnea, or voice changes suggest tracheal or esophageal compression 5
• Rapid growth has occurred, which is one of the strongest predictors of malignancy 2
• Firm, fixed texture on palpation indicates possible extrathyroidal extension 2
• Cervical lymphadenopathy is palpable, raising concern for metastatic thyroid cancer 1, 2
• High-risk history exists—prior head/neck irradiation (7-fold increased cancer risk), family history of thyroid cancer, or age <15 years 2, 5

Routine scheduling (within 2-4 weeks) is acceptable if:

• The goiter is asymptomatic, soft, mobile, and longstanding without recent change 1
• No palpable nodules or lymphadenopathy are detected on examination 1

What Happens After Ultrasound

The ultrasound findings will determine next steps:

• Discrete nodules ≥1 cm with suspicious features (solid, hypoechoic, microcalcifications, irregular margins) → ultrasound-guided fine-needle aspiration 2, 5
• Nodules <1 cm with high-risk features (subcapsular location, suspicious lymph nodes, radiation history) → consider FNA 2, 5
• Diffuse enlargement without discrete nodules → measure TSH; if elevated, diagnose hypothyroidism; if suppressed, proceed to radioiodine uptake scan to differentiate Graves' disease from toxic multinodular goiter 1, 5
• Suspicious lymph nodes → FNA with washout for thyroglobulin measurement 1, 5

Common Pitfalls to Avoid

Do not order radionuclide scanning (thyroid scintigraphy) in euthyroid patients—it does not help distinguish benign from malignant nodules and delays definitive diagnosis 1, 2. Scintigraphy is reserved for patients with suppressed TSH (thyrotoxicosis) to identify autonomous function 1, 5.

Do not rely on CT or MRI as initial imaging—these modalities are inferior to ultrasound for nodule characterization and should be reserved for suspected substernal extension or invasive cancer 1. CT with iodinated contrast can also delay subsequent radioiodine therapy if cancer is diagnosed 1.

Do not assume a "normal" TSH excludes malignancy—most thyroid cancers occur in euthyroid patients with normal thyroid function 2, 5. TSH measurement is important for management but does not replace ultrasound evaluation 5.

Do not skip ultrasound even if the goiter feels benign—palpation cannot reliably differentiate benign from malignant pathology, and surgeon-performed ultrasound has been shown to alter treatment plans in 17.6% of cases by identifying occult nodules or lymphadenopathy 6, 7.