Thyroid nodules, goitre and thyroid cancer — viva

Stem

Examiner-led viva on a paediatric thyroid nodule. [1]

Examiner: What is your first investigation and why? [1]

Strong answer: TSH with reflex free T4 to establish functional status. A suppressed TSH with a solitary nodule suggests a hyperfunctioning lesion that is almost always benign and needs functional imaging, not FNA; a normal TSH never excludes malignancy, so it does not end the structural workup. [1] [5]

Examiner: How do you triage the nodule on imaging? [1]

Strong answer: High-frequency thyroid ultrasound applying the ACR TI-RADS system — scoring composition, echogenicity, shape, margin and echogenic foci into a tier TR1 to TR5 with size-based FNA thresholds — while mapping the cervical lymph nodes, because suspicious nodes are biopsied alongside the nodule. [1] [2]

Examiner: The FNA returns Bethesda III (indeterminate). What now? [1]

Strong answer: Apply molecular testing to detect fusion or mutation events that reclassify risk — children are dominated by gene fusions (RET/PTC, ETV6::NTRK3, ALK, BRAF fusions) rather than the BRAF V600E point mutation common in adults — and convene the multidisciplinary team to decide on lobectomy versus total thyroidectomy based on the molecular probability and family preference. [1] [10]

Examiner: Bethesda VI (malignant) with a positive central node. Who operates? [1]

Strong answer: A high-volume thyroid surgeon within a paediatric multidisciplinary thyroid team performs total or near-total thyroidectomy with central neck dissection, because complication rates — recurrent laryngeal nerve injury and hypoparathyroidism — are operator-dependent and lifelong in a child. [9] [20]

Examiner: Do all children get radioiodine? [1]

Strong answer: No. The ATA 2015 paediatric risk stratification assigns low, intermediate or high risk; radioiodine (I-131) is selective — reserved for intermediate- and high-risk differentiated disease — with TSH suppression during active disease and relaxation once in durable remission. [1]

Examiner: How do you follow up long term? [1]

Strong answer: Thyroglobulin (Tg) trend alongside neck ultrasound, with stimulated Tg and cross-sectional or functional imaging if recurrence is suspected; response is structural and biochemical remission (undetectable Tg, negative imaging), with a structured transition to adult thyroid services. [1]

Examiner: What if calcitonin is markedly raised instead? [13]

Strong answer: That shifts the diagnosis to medullary (C-cell) carcinoma — calcitonin-secreting, RET/MEN2-related, not radioiodine-avid — so I add RET testing and genetic counselling, plan total thyroidectomy with central node dissection, and run lifelong calcitonin and CEA surveillance; in known germline RET carriers, prophylactic thyroidectomy is offered at a codon-determined age. [13]