Figure 1.

Flowchart of initial evaluation, treatment, and follow-up of the pediatric thyroid nodule. ^#The expert panel suggests considering the measurement of serum calcitonin in children suspect of MTC based on individual conditions and the preference of the physician (Recommendation 5A). The expert panel suggests that, in selected cases (conditions which suggest MEN2, a positive family history of MEN2, or in case of bulky thyroid disease), measurement of calcitonin may be of additional value for early diagnosis of MTC (Recommendation 5B). ^*Malignancy risk (suspicious vs no suspicion) is based on neck ultrasound characteristics (37), section ‘B2. Risk of malignancy in a thyroid nodule during childhood’), history of radiation, and (signs of a) pre-disposition syndrome. If there is a significant increase in nodule size or the ultrasound characteristics change over time, (repeated) FNB should be performed. ^**Analysis of the presence of other oncogenic drivers and gene fusions (e.g. RET/PTC and NTRK-fusions) may be considered in Bethesda 3, 4, or 5 due to the fact of increasing awareness that these are also associated with the presence of PTC (39). In case a BRAF V600E mutation is found, the risk of the thyroid nodule being malignant is high but needs to be confirmed, for example, by frozen section during thyroid surgery. ^{^}Total thyroidectomy after proven presence of MTC. ^{^^}Alternatively, FNB can be performed; in case of DTC, a total thyroidectomy should be performed.