Role of Thyroid Ultrasound in the Diagnosis of Thyroid Nodules with Atypia of Undetermined Significance.

Objective To evaluate the role of ultrasound for thyroid nodules with atypia of undetermined significance(AUS).Methods From January 2014 to December 2015,83 thyroid nodules with AUS diagnosed by ultrasound-guided fine-needle aspiration biopsy were collected from 1984 subjects. On the basis of ultrasonic features,each thyroid nodule was prospectively classified into one of three categories: low suspicion for malignancy,intermediate suspicion for malignancy,and high suspicion for malignancy. Results Among 83 lesions,19 lesions(22.9%) were confirmed malignant,8 lesions (9.6%)were benign,56 lesions (67.5%)had no abnormal changes during clinical follow-up. The nodules were solitary in 36 cases (43.4%)and multiple in 47 cases(56.6%).The maximum diameter was (1.2±0.7)cm. Based on the ultrasonic feature of 19 malignant cases,16 cases (84.2%) were classified as high suspicion for malignancy,2 cases(10.5%) as intermediate suspicion for malignancy,and 1 case(5.3%) for low suspicion for malignancy. Univariate and multivariate analyses revealed that the degree of malignancy of thyroid nodules was significantly associated with ultrasound image classification[OR=9.23(2.96-28.79),P=0.00],but not with age,gender,nodule number,and nodule size (all P>0.05).Conclusion Ultrasound diagnosis by using the present thyroid ultrasound classification system can be helpful for distinguishing malignant and benign AUS thyroid nodules.