Fig. 1. Examples of nodules suspected as malignant on US findings. (A) A 6-mm suspicious nodule (delineated by electronic calipers) was found on the right thyroid gland, and PTC was confirmed by surgical pathology. (B) A 7-mm suspicious nodule (delineated by electronic calipers) was found on the right thyroid gland and was cytologically confirmed as FLT more than twice by FNAB. The thyroid gland showed diffuse heterogeneous echogenicity, a characteristic finding of the DTD pattern of thyroid gland on US. (C) There was a 6-mm suspicious nodule (delineated by electronic calipers) on the left thyroid gland, which was cytologically confirmed as AH more than twice by FNAB. PTC, papillary thyroid cancer; FLT, focal lymphocytic thyroiditis; AH, adenomatous hyperplasia; FNAB, fine needle aspiration biopsy; DTD pattern, "diffuse thyroid disease" pattern on US; US, ultrasound.