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Abstract

Case Presentation: A 58-year-old male patient presented with a 1-year history of an enlarging left-sided neck mass. There was no obvious dysphagia, stridor, or symptoms of hyperthyroidism or hypercalcemia. On examination, there was a firm, painless mass in the left thyroid lobe. Biochemical testing revealed normal thyroid function tests but elevated serum calcium of 3.01 mmol/L (normal, 2.2 to 2.5 mmol/L), creatinine 124 μmol/L (normal, 64 to 111 μmol/L), parathyroid hormone (PTH) 57.0 pmol/L (normal, 1.6 to 7.9 pmol/L), and decreased phosphate 0.65 mmol/L (normal, 0.74 to 1.52 mmol/L). Thyroid ultrasonography showed a giant hypoechoic nodule in the left lobe, measuring 5.6 × 3.8 cm. Pertechnetate sestamibi parathyroid scintigraphy demonstrated intense activity in the left thyroid bed (Fig. 1), which was shown as a hypodense mass with a dot calcification and clear rim in the left thyroid lobe by single photon emission–computed tomography (Fig. 2). What is the diagnosis? Fig. 2 View Large Image Figure Viewer