Fig. 1

US showed a mass close to the lower side of the right thyroid lobe and a cystic solid mass in the sheath of the left carotid artery (A); MRI showed a cystic solid mass in the sheath of the left carotid artery, about 48 mmX25 mmX39 mm in size, with clear boundary. The solid part showed slightly low signal intensity on T1WI and slightly high signal intensity on T2WI, and the cystic part showed uniform high signal intensity on T1WI and T2WI (B); MIBI showed an uptake in the right inferior parathyroid mass (C); CT revealed a 46 mmx23 mm mass in the sheath of the left carotid artery (D); The postoperative MIBI examination was negative (E); The neck US image of the left neck mass (F)