Hyperparathyroidism associated with the enlargement of two or three parathyroid glands.

Eighty-five (23%) of 375 patients undergoing surgery for primary hyperparathyroidism were found to have enlargement (greater than 50 mg) of two or three parathyroid glands. Of 76 patients followed from 12 to 140 months after surgery, eight (10.5%) developed hypercalcemia at 1, 4, 45, 64, 74, 79, 84, and 133 months. In a comparison of pertinent preoperative biochemical and pathologic data between 55 patients with two- or three-gland hyperparathyroidism and 55 age- and sex-matched patients with single-gland hyperparathyroidism, only the preoperative serum phosphate differed significantly, being lower in the patients with single-gland disease (2.4 +/- 0.1 vs. 2.6 +/- 0.1; p less than 0.04). In the eight patients with two- or three-gland hyperparathyroidism who developed postoperative hypercalcemia, the preoperative concentrations of serum calcium were lower (10.8 +/- 0.2 vs. 11.5 +/- 0.2; p less than 0.019), the preoperative concentrations of serum phosphate were higher (3.1 +/- 0.2 vs. 2.5 +/- 0.1; p less than 0.020), and the weights of the excised parathyroid tissues were less (356 +/- 72 mg vs. 1354 +/- 215 mg; p less than 0.02) than those of patients with two- or three-gland disease who did not develop postoperative hypercalcemia, indicating a milder form of hyperparathyroidism. In the 68 patients without recurrent hypercalcemia, there was no tendency for the serum calcium concentration to increase with time. Patients with primary hyperparathyroidism associated with two or three enlarged parathyroid glands have an appreciable incidence of persistent or recurrent hypercalcemia, which may increase even further with longer observation.