Ultrasonographic features and management of thyroid nodules undergoing ultrasound-guided fine needle aspiration

Abstract

INTRODUCTION: Thyroid nodules can be detected in 50 to 60% of healthy individuals, particularly in the elderly and females. An increase in differentiated thyroid cancer has been noted over the years, especially papillary thyroid cancer.

OBJECTIVES: To assess different approaches to management and histological nature of thyroid nodules in Malta, as well as to evaluate the association of ultrasound characteristics with biochemical and histological features.

METHODS: All thyroid nodules undergoing ultrasound-guided fine needle aspiration (FNA) between July 2013 and December 2017 were evaluated. Data was collected on ultrasonographic nodule characteristics, FNA histology (using Bethesda system), follow-up of these nodules with repeat ultrasound or FNA and histology report of those nodules undergoing surgery. Sensitivity and specificity of thyroid nodule FNA was calculated.

RESULTS: A total of 1420 patients who had 1522 FNAs were identified. They had a mean age of 57.4 (+/− 15.3) years at the time of FNA and the majority (76.1%) were female. Most nodules were benign (69.3%), while only 1.9% and 4% were suspicious of malignancy or malignant respectively. Lobectomy or total thyroidectomy was undertaken in 21.5% of patients. Of those operated 19.6% had a follicular adenoma, 4.6% had a follicular carcinoma, 35.6% had papillary carcinoma, 1.3% medullary carcinoma, 0.3% anaplastic and 41.8% had benign nodules, with multinodular goitre predominating in 69.5% of benign cases. Where documented on ultrasound, most malignant nodules were at least 2 cm in size (37.2%), had chaotic intranodular vascularity (35.7%), were hypoechoic (62%), had irregular borders (22.6%) and microcalcifications (27.7%). The sensitivity and specificity of FNA cytology for malignancy (including both Bethesda categories 5 and 6) were 85.3% and 95.1% respectively.

CONCLUSION: Our sensitivity and specificity results for FNA cytology compare well with ranges quoted by current guidelines. Papillary carcinoma was found to be the most prevalent thyroid malignancy in Malta.