Fig 2.
The 5 US categories for solid Bethesda class III nodules. A, Benign: transverse US image of a left thyroid nodule (approximately 2.7 × 4.2 × 5.4 cm3) with isoechogenicity, smooth margin, and an ovoid shape (nodular hyperplasia in pathology) in a 25-year-old woman. B, Probably benign: longitudinal US image of a right thyroid nodule (approximately 1.0 × 1.1 × 1.1 cm3) with isoechogenicity, some lobulated margin, and a round shape (follicular variant of papillary thyroid carcinoma pathologically) in a 52-year-old woman. C, Borderline: transverse US image of a right thyroid nodule (approximately 0.5 × 0.6 × 1.1 cm3) with eggshell calcification (with a focal defect and thickenings of an eggshell) and an ovoid shape (classic type of papillary thyroid carcinoma pathologically) in a 47-year-old woman. D, Possibly malignant: longitudinal US image of a right thyroid nodule (approximately 0.5 × 0.5 × 0.5 cm3) showing hypoechogenicity, a spiculated margin, and a round shape (classic type of papillary thyroid carcinoma pathologically) in a 53-year-old woman. E, Malignant: transverse US image of a right thyroid nodule (approximately 0.9 × 1.0 × 1.0 cm3) showing marked hypoechogenicity, macrolobulation, and taller-than-wide shape (follicular variant of papillary thyroid carcinoma pathologically) in a 70-year-old woman.