Part of “CHAPTER 58 – PRIMARY HYPERPARATHYROIDISM“

Parathyroid carcinoma is a rare form of primary hyperparathyroidism.108,109 These patients often have hypercalcemia that is more severe than that usually seen in primary hyperparathyroidism. Serum calcium values >14 mg/dL may suggest a parathyroid malignancy. However, parathyroid carcinoma is uncommon, occurring in <0.5% of patients with primary hyperparathyroidism. Making the clinical diagnosis of parathyroid carcinoma before surgery is often difficult. Along with the high serum calcium level, the PTH level tends to be markedly elevated. Patients with parathyroid carcinoma often have coexistent complications related to the skeleton and the kidney. This combination is unusual in benign primary hyperparathyroidism. Another striking feature may be a palpable neck mass. The
clinical features of palpable neck mass, marked hypercalcemia, high concentrations of PTH, and coexistent skeletal resorption and kidney stones should alert the clinician to the possibility of parathyroid carcinoma.110 The diagnosis of parathyroid carcinoma may not be made until the time of surgery. The gross appearance of the parathyroid tissue may indicate the diagnosis. At times, the histologic features of parathyroid carcinoma may be typical (see Chap. 48), or it may be difficult to diagnose. Surgery is the mainstay of therapy for parathyroid carcinoma.