A 52-year-old woman presents with a hard, palpable left neck mass, serum calcium of 15.2 mg/dL, and intact PTH of 1450 pg/mL (normal 15 to 65 pg/mL). Hoarseness is present. Sestamibi shows a large left inferior gland. Which intraoperative and pathological finding best supports the suspected diagnosis?

• A A well encapsulated tan-brown gland weighing 500 mg with chief cell hyperplasia
• B Water-clear cell hyperplasia involving all four glands symmetrically
• C Ectopic gland located within the thymus requiring median sternotomy
• D Thick fibrous capsule with capsular and vascular invasion by atypical parathyroid cells ✓

Explanation

The combination of extreme hypercalcaemia above 14 mg/dL, PTH five to ten times normal, a palpable neck mass and hoarseness suggests parathyroid carcinoma. Definitive diagnosis rests on capsular, vascular or perineural invasion and trabecular architecture with mitoses, since cytology alone cannot distinguish it from adenoma. Benign adenomas are usually under 2 g without a palpable mass, and hyperplasia involves all four glands with milder biochemical derangement.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.