Ultrasound predictors of malignancy in indeterminate thyroid nodules

Asymptomatic thyroid nodules are an increasingly common clinical problem. Lesions greater than a centimetre require cytological assessment. Indeterminate lesions often need surgical excision to establish a definitive diagnosis and plan further management. If a definitive diagnosis could be accurately predicted pre-operatively, the most appropriate surgical procedure could be performed at the initial operation.

The aim of this study was to identify whether specific thyroid ultrasound features could predict malignancy in indeterminate thyroid nodules.

A retrospective review of all patients undergoing surgery for an indeterminate thyroid lesion between 2006 and 2012 was performed. Demographic features, surgical intervention and final histological findings were determined. Pre-operative ultrasound findings and final histology were correlated and the ultrasonic markers predictive of malignancy were determined.

A total of 40 patients were identified as having undergone surgical intervention for indeterminate thyroid nodules. The majority of patients were diagnosed with a follicular adenoma (n = 22; 55 %). Papillary thyroid carcinoma was identified in three patients (7.5 %) and follicular carcinoma in a further 3 (7.5 %). Ultrasound features associated with malignancy included poorly defined nodule borders and increased vascularity. The presence of malignancy was not related to nodule size, echogenicity or the presence of calcifications.

The majority of indeterminate thyroid lesions are benign on final histological assessment. High nodule vascularity associated with ill-defined borders is associated with malignancy. Further research is warranted to identify predictors of malignancy in indeterminate nodules in order to avoid unnecessary or repeated procedures.