Fig. 1

A 45~ 50-year-old patient with tumor recurrence/persistence of papillary thyroid carcinoma (PTC) in a regional lymph node. Before thyroid surgery, a longitudinal gray-scale sonogram (a) showed a primary PTC in the right lobe (9.6 mm in the largest diameter). On the 44-month follow-up ultrasonography after total thyroidectomy, transverse (b) and longitudinal (c) gray-scale sonograms showed a suspicious lymph node with intranodal microcalcifications and diffusely increased echogenicity in the right lower neck (arrows, 6.6 × 8.2 × 11.0 mm). On the transverse color-Doppler sonogram (d), a suspicious lymph node showed an increased vascularity. After US-guided fine-needle aspiration for this node, nodal metastasis of PTC was diagnosed on cytology. After consecutive nodal dissection, nodal metastasis was confirmed on histopathological analysis