Updated guidelines for the diagnosis and management of thyroid nodules

Abstract

The incidental detection of thyroid nodules by ultrasound (US) is increasing explosively. The clinical significance of these nodules is that 5% to 15% of them are malignant, requiring adequate treatment including surgery. Clinical guidelines for the management of thyroid nodules has been published and revised by many thyroid associations around the world in the past decade. The Korean Endocrine Society has also published guidelines for the management of thyroid nodules and thyroid cancer, and the Korean Thyroid Association has recently revised these guidelines. The revised guidelines include the size criteria for which fine needle aspiration cytology (FNAC) is warranted and the Bethesda system, a new cytologic diagnosis system in which thyroid nodules are classified by the degree of malignancy potential. US is recommended to evaluate thyroid nodules in detail. FNAC should be performed for the suspicious cervical lymph nodes regardless of their size and for thyroid nodules larger than 0.5 cm in patients with clinically high risk history and sonographically suspicious findings. Otherwise, FNAC is indicated for thyroid nodules larger than 1 cm in diameter. Repeated FNAC is indicated for nodules with cytologic diagnosis of ‘nondiagnostic’ or ‘atypical cell of unknown significance’. Surgery is needed for nodules diagnosed as ‘follicular neoplasm (Hurthle cell type)’, ‘suspcious for malignancy’ and ‘malignancy’. For ‘benign’ nodules, only follow-up with US+/-FNAC is needed. Well-designed studies on thyroid nodules in Korean patients would provide evidence for Korean guidelines for thyroid nodules. Conclusion: The revised Korean Thyroid Association guidelines for thyroid nodules are very useful for managing patients.