A 41-year-old man presented with a 1-year history of a slowly expanding right neck mass (Figure 1). During the past few months, he had also developed diffuse bone pain and had recently begun to use a cane to walk. The patient's medical history was significant for end-stage renal disease as a sequela of Wegener granulomatosis; he had been receiving hemodialysis for more than 10 years. Five years ago, the patient underwent neck surgery, although he was unable to provide specific details. Physical examination revealed a transverse Kocher incision and a 2-cm round, mobile mass in the right neck at level III. Laboratory testing revealed hypercalcemia (total calcium level, 11.7 mg/dL; reference range, 8.0-10.4; to convert to millimoles per liter, multiply by 0.025) and elevated parathyroid hormone level (>2500 pg/mL; reference range, 12-65 pg/mL).
A computed tomographic scan with intravenous contrast demonstrated a 2.1 × 1.5 × 2.0-cm, heterogeneously enhancing mass located within the right sternocleidomastoid muscle. There was a small amount of low attenuation at the periphery of the lesion, and there was associated fat stranding of the adjacent subcutaneous tissue (Figure 2). Fiberoptic laryngoscopy revealed mobile vocal cords.
A. Ectopic parathyroid adenoma
B. Secondary hyperparathyroidism
C. Tertiary hyperparathyroidism
D. Medullary thyroid cancer with lateral neck and bone metastases
Answer