Ultrasonographic features of thyroid nodules accompanied by Hashimoto thyroiditis

To compare the ultrasound imaging characteristics of benign and malignant thyroid nodules on the background of Hashimoto's thyroiditis (HT).

Totally 120 consecutive patients with pathologically confirmed benign (n=60) or malignant (n=60) thyroid nodules in Peking Union Medical College Hospital since January 2013 were retrospectively analyzed, and their preoperative ultrasound images were reviewed.

Sixty cases (100%) of the malignant nodules were papillary thyroid cancers. In the benign group, 33 cases (55.0%) had nodular changes of HT, 26 (43.3%) had nodular goiter, and one (16.7%) had adenoma. Compared with the benign ones,the malignant nodules were more likely to be solid (91.7% vs. 68.3%, P=0.001), hypoechoic (96.7% vs. 48.3%, P=0.000), ill defined (95.0% vs. 41.7%, P=0.000), irregular (96.7% vs. 43.4%, P=0.000), and more easily to have such characteristics as micro-calcification (71.7% vs. 30.0%, P=0.000), absence of regular halo (96.7% vs. 65.0%, P=0.000), taller-than-wide sign (46.7% vs. 13.3%, P=0.000), and locally increased or irregular blood flow (61.7% vs. 26.7%, P=0.000).

Ultrasound has an ideal overall sensitivity in differentiating nodules on the background of HT. Solid structure, hypo-echogenicity, ill-defined margin, irregular shape, and absence of regular halo are good screening ultrasound markers. Except for the A/T≥1, the other variables have less satisfactory diagnostic specificity.