Thyroid nodules: diagnosis and management

Summary

• 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.