Approach to thyroid nodules in children and adolescents.

Thyroid nodule prevalence is about 1.8% in healthy children; however, malignancy frequency is higher than in adults. Approximately 26.4% of thyroid nodules generate thyroid cancer in childhood. Coexisting thyroid disease, history of irradiation of the neck, post-pubertal age, female sex, and thyroid malignancy in the family are risk factors for developing nodules. After evaluation of the medical history and detailed physical examination, the second step is assessment of thyroid function and measurement of calcitonin level. Thyroid stimulating hormone (TSH) value in the upper range seems to be correlated with cancer. Calcitonin levels must be evaluated, especially if medullary cancer is suspected. Ultrasonography (USG) is the first-line imaging tool in the diagnosis of thyroid nodules. It gives information about the nodule size, echogenicity and location. Hypoechogenicity, microcalcifications, undefined margins, high internodular vascular flow, and subcapsular localization are clues of malignant lesions. Scintigraphy is only recommended in a solid nodule with the presence of suppressed TSH. Fine-needle aspiration biopsy (FNAB) has 90% accuracy and is very useful in the selection of patients for surgery. It must be applied to all nodules ≥1 cm and nodules ≤1 cm suspicious for malignancy. The other diagnostic tools are elastography, immunocytochemical markers and genetic evaluation. In the management of thyroid nodules, surgery is advised, especially if there is difficulty in distinguishing benign lesions from carcinoma.