Thyroid nodules, goitre and thyroid cancer — formative SAQs

SAQ 1 (10)

A 14-year-old girl finds a painless lump in her right neck. Examination shows a 2 cm firm but mobile right-lobe thyroid nodule with no cervical lymphadenopathy and a normal voice. She is clinically euthyroid with no prior radiation and no family history of thyroid cancer. ^[1]

1. Outline the investigation sequence for this nodule. (3) ^[1]
2. State the role of ACR TI-RADS and Bethesda cytology. (3) ^{[1] [2]}
3. Give two red-flag features that would accelerate referral. (2) ^[1]
4. Why is the malignancy risk higher than in an adult? (2) ^[5]

Model answer

Investigation sequence. TSH with reflex free T4 to establish functional status (a suppressed TSH with a solitary nodule suggests a hyperfunctioning, almost always benign lesion); high-frequency thyroid ultrasound applying ACR TI-RADS to the nodule and mapping cervical nodes; ultrasound-guided FNA of any nodule meeting TI-RADS threshold, reported with Bethesda cytology; add molecular testing if the cytology is indeterminate. ^[1]

TI-RADS and Bethesda. TI-RADS scores composition, echogenicity, shape, margin and echogenic foci into a tier (TR1 benign to TR5 highly suspicious) with size-based FNA thresholds — here a 2 cm TR4 lesion meets the threshold. Bethesda cytology assigns one of six categories (I non-diagnostic through VI malignant) whose malignancy risk frames the next step; Bethesda V/VI prompts multidisciplinary surgical referral. ^{[1] [2]}

Red flags. Firm or fixed mass with new hoarseness (recurrent laryngeal nerve), and associated firm or matted cervical lymphadenopathy; others include rapid growth and compressive symptoms. ^[1]

Higher paediatric risk. Childhood nodules carry roughly 20–25% malignancy risk — about double the adult ~10–15% — reflecting a more aggressive biological substrate and the gene-fusion driver profile distinct from adult BRAF V600E point-mutation disease. ^[5]