SFEIES24 Poster Presentations Thyroid (21 abstracts)
1Department of Endocrinology, Beaumont Hospital, Dublin, Ireland; 2Department of Surgery, Beaumont Hospital, Dublin, Ireland; 3Department of Radiology, Beaumont Hospital, Dublin, Ireland; 4Department of Histopathology, Beaumont Hospital, Dublin, Ireland
Background: Thyroid nodules incidentally picked up on imaging studies are extremely common with a prevalence of around 50% in the general population. Ultrasound characterization using the British Thyroid Association (BTA) U classification system is commonly employed in the United Kingdom and Ireland. Most reported nodules are classified as U3 which indicates an indeterminate suspicion of malignancy. There are limited data on the malignancy rates in U3 nodules.
Methods: We examined the malignancy rate among U3 thyroid nodules that underwent fine needle aspiration cytology (FNAc) in our unit. FNAc was reported using the Royal College of Pathologists Thy classification (Thy1-Thy5).
Results: Eighty three U3 nodules underwent FNAc. The median size was 2.8cm in the largest diameter (range 0.8-8.6cm). Thirteen nodules were initially reported as Thy1 (inadequate sample). Repeat aspirates or follow up surveillance scans diagnosed 1 cancer. Fifty-three were initially reported as Thy 2 (benign). One of those was later diagnosed as papillary thyroid cancer following repeat aspirate and surgery. Sixteen were reported as Thy3 (indeterminate) with 1 malignancy diagnosed subsequently. One nodule was reported as Thy5 (malignant). Overall, 3/83 nodules were malignant (3.6%).
Conclusion: Malignancy rate among U3 thyroid nodules is low and similar to that reported with indeterminate nodules using other Ultrasound classification systems.