Neck Imaging:
Ultrasound showed significant enlargement of both thyroid remnants. The right lobe measured 56 × 43 × 30 mm and the left 60 × 38 × 35 mm. The thyroid tissue was heterogenous with multiple well-defined nodules of various sizes. The largest nodules were TR3 in category, measuring 48 × 42 × 25 mm (right) and 36 × 30 × 27 mm (left). Mildly increased vascularity and macrocalcifications were noted. Mild left-sided retrosternal extension was observed. Additionally, an intrathyroidal solid hypoechoic nodule with partial retrosternal extension on the left side raised suspicion of either a TR4 thyroid nodule or parathyroid adenoma. Subsequent parathyroid scintigraphy supported the diagnosis of a parathyroid lesion.

• Thyroid Gland: The thyroidectomy specimen showed a unifocal 1.8 cm conventional papillary thyroid microcarcinoma in the right lobe with lymphovascular and perineural invasion. No extrathyroidal extension was noted. Three right lower neck lymph nodes were positive for metastatic papillary carcinoma with extranodal extension. Final staging was pT1b N1b. The background thyroid tissue showed follicular nodular disease with focal lymphocytic thyroiditis.

• Right Neck Mass: Confirmed as metastatic papillary thyroid carcinoma involving all three dissected lymph nodes with extranodal extension. Largest metastatic focus was 0.8 cm.

• Left Intrathyroidal Nodule: Diagnosed as parathyroid carcinoma, showing capsular infiltration and extensive vascular invasion (more than four foci). Tumor was at least 3 cm in size (disrupted). Focal necrosis and atypia were noted, with a sparse lymphocytic reaction. No perineural invasion was observed. Final staging was pT2 N0.