- Thyroid nodules are common. Their importance lies in the need to assess thyroid function, degree of and future risk of mass effect, and exclude thyroid cancer, which occurs in 7–15% of thyroid nodules.
- There are four key components to thyroid nodule assessment: clinical history and examination, serum thyroid stimulating hormone (TSH) measurement, ultrasound and, if indicated, fine-needle aspiration (FNA).
- If the serum TSH is suppressed, a thyroid scan with 99Tc can distinguish between a solitary hot nodule, a toxic multinodular goitre or, less commonly, thyroiditis or Graves’ disease within a coexisting nodular thyroid. Scintigraphically cold nodules are evaluated in the same way as in the setting of normal or elevated serum TSH levels.
- Thyroid ultrasonography should be performed only for palpable goitre and thyroid nodules and by specialists with expertise in thyroid sonography.
- Routine thyroid cancer screening is not recommended, except in high risk individuals, as the detection of early thyroid cancer has not been shown to improve survival.
- FNA may be performed for nodules ≥ 1.0 cm depending on clinical and sonographic risk factors for thyroid cancer.
- FNA specimens should be read by an experienced cytopathologist and be reported according to the Bethesda Classification System.
- Molecular analysis of indeterminate FNA samples has potential to better discriminate benign from malignant nodules and thus guide management.
- Surgery is indicated for FNA findings of malignancy or indeterminate cytology when there is a high risk clinical context. Surgery may also be indicated for suspicion of malignancy; larger nodules, especially with symptoms of mass effect; and in some patients with thyrotoxicosis.
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