- The majority of thyroid nodules are benign and do not require surgery
- Not all thyroid cancers require surgery; some differentiated thyroid cancers can be monitored with close follow-up
- Objectives of evaluation of a thyroid nodule / mass
- Avoid unnecessary surgery
- Do appropriate surgery
- Avoid doing harm e.g. causing RLN injury, hypocalcaemia and/or hypothyroidism when calcium monitoring and replacement therapy are unavailable
- Ultrasound is the best imaging modality for thyroid nodules. It has a high sensitivity and specificity for diagnosis of thyroid malignancy
- When ultrasound is unavailable, then history and physical examination of the thyroid and neck may yield features suggestive of higher risk of malignancy e.g. rapid growth, firm mass, thyroid asymmetry, cervical lymphadenopathy, recent onset of hoarseness, and vocal cord paralysis. Presence of multiple suspicious features e.g. firm thyroid mass with hoarseness, is associated with a higher risk of malignancy. When ultrasound is unavailable, these features are indications for FNAC
- Only if ultrasound is unavailable, may CT or MRI be considered to assess a thyroid nodule with the knowledge that they have poorer sensitivity and specificity and are more expensive
- With FNAC, Bethesda IV only has a 20 – 30% risk of being a follicular carcinoma
- A thyroid uptake scan is not indicated for the workup of a thyroid nodule unless the patient is biochemically or clinically thyrotoxic
- When TSH is not available, clinical signs and symptoms may be used to determine the probability of a hyperthyroid vs. euthyroid/hypothyroid state. A clinically validated method is Wayne’s Index, with reported positive predictive value of 95% and negative predictive value of 90% (Naraintran S et al. Accuracy of Wayne’s criteria in diagnosing hyperthyroidism: a prospective study in south Kerala, India. Int Surg J 2018; 5:1267-70)
- Thyroid lobectomy is the minimum recommended resection but, diagnostic nodulectomy may occasionally be necessary in situations where FNAC is not available, where the nodule is in the isthmus or positioned anteriorly within the thyroid and where there is concern about hypothyroidism in a context where thyroid replacement is unavailable.
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