A man in his 20s presented for further evaluation of an elevated serum ionized calcium level (6.28 mg/dL; reference range, 4.56-5.32 mg/dL) found incidentally during a routine examination 5 months prior. He had a several-year history of joint, back, and abdominal pain; constipation; fatigue; and depression. Laboratory workup revealed a normal intact parathyroid hormone (PTH) level (50 pg/mL; reference range, 13-88 pg/mL) and a slightly elevated 24-hour urinary calcium level (314 mg/d; reference range, 25-300 mg/d). A technetium Tc-99m sestamibi scan showed no definitive lesion but demonstrated a small focus of possible increased tracer uptake near the mid-pole of the left thyroid lobe (Figure, A, arrowheads). No abnormal masses were readily identifiable by ultrasonography or contrast-enhanced computed tomography (CT) of the neck. He underwent a parathyroid exploration and excision of a soft, ovoid tissue, believed to be a slightly enlarged left inferior parathyroid gland (120 mg; 1.0 × 0.6 × 0.3 cm). Intracytoplasmic fat vacuoles were evident on intraoperative touch preparation. Histological examination of permanent sections showed a thinly encapsulated parathyroid tissue (Figure, B) with approximately 30% displaying myxoid stromal change and focal presence of interspersed adipocytes (Figure, C, yellow arrowhead) bordered by a rim of compressed gland containing abundant stromal fat (Figure, C, blue arrowhead). Examination at higher power showed chief cells in lobules, nests, and focal trabeculae with occasional clusters of clear and oxyphil cells (Figure, C and D).
Canfarotta M, Hegde P, Parham K. Hypercalcemia in a Young Man. JAMA Otolaryngol Head Neck Surg. 2016;142(11):1125-1126. doi:10.1001/jamaoto.2016.0072