<prompt> Malignant cold nodule in thyroid diagnostic on USG by all EXCEPTNo cystic lesionIrregular marginsCalcification at margin of tumourHypoechoic  <response>: A No cystic lesion USG can also be used to aid in the differentiation between benign and malignant nodules. The following criteria can be used by USG, and favor a diagnosis of malignancy:1 Absence of a halo sign2 Uniformly solid tumor with occasional central necrosis3 Irregular margins4 Fine calcifications5 Heterogenous echos and large size6 Surrounding tissue invasion 