TPO and thyroiditis: However, the AUS/FLUS with CLT group had a higher percentage of females (88% vs. 71%), smaller tumors (mean size, 1.9 cm vs. 2.4 cm), frequent diffuse or focal thyroiditis on US (39% vs. 14%), lymphocytic thyroiditis background on FNAC (18% vs. 4%), higher concentrations of serum TSH (mean, 2.87 mU/L vs. 1.65 mU/L), anti-TPO antibody (mean, 905 U/mL vs. 68 U/mL), and anti-TG antibody (mean, 180 U/mL vs. 19 U/mL), and a higher rate of thyroid medication at baseline (9% vs. 3%) than the AUS/FLUS without CLT group.