Endocrine Abstracts

Introduction: Approximately 400 thyroid fine needle aspirates (FNAs) are performed annually at our institution. Many are repeat aspirates of Thy2 results. Current British Thyroid Association (BTA) and Royal College of Pathologists (RCPath) guidelines recommend two FNAs performed at least 6 months apart to confirm a benign result. Our aim was to investigate whether one Thy2 result is sufficient to confirm benign pathology.

Method: A retrospective analysis was performed on all 416 thyroid FNAs carried out in the year 2010. 312 of these were Thy2. Of these Thy2 results only 92 patients were subject to a second confirmatory FNA. Nine patients had two distinct nodules that were sampled twice giving 101 repeat sampling events.

Results: The second FNA was Thy1 in nine cases, Thy2 in 86 cases, and Thy3 in six cases. Of the six Thy3 results, all had surgery and histology revealed five were benign and one malignant. In the malignant case, the first ultrasound guided FNA of the nodule although reported as Thy2 was said to show granulomatous thyroiditis. After an interval review the lump was noted to be hard and fixed. Ultrasound showed increase in size with irregular margins and repeat FNA showed lymphoid cells raising the possibility of lymphoma. Thyroidectomy revealed diffuse large B-cell lymphoma.

Conclusion: We perform repeat FNAs in only 32% of initial Thy2 results with a very low false negative rate. We propose that, in the majority of thyroid nodules, one Thy2 ultrasound guided thyroid FNA result is sufficient to make a robust benign diagnosis. Repeat testing should only be performed in those patients with suspicious or higher risk clinical or US features.