Primary hyperparathyroidism and nonmedullary thyroid cancer.

Of 2,058 patients who had surgically proven primary hyperparathyroidism at the Mayo Clinic from 1965 through 1979, 51 or 2.5 percent had associated nonmedullary thyroid carcinoma. A history of radiation exposure to the head and neck was obtained in 14 of 43 patients questioned. Thyroid disease consisted of grade 1 papillary adenocarcinoma in 48 cases and pure follicular adenocarcinoma in 3 cases. The parathyroid disease included 41 single adenomas and 5 cases of parathyroid hyperplasia; 5 patients had 2 adenomas. At follow-up, none of the patients had evidence of metastatic thyroid carcinoma. Ten patients were receiving calcium or vitamin D supplementation for protracted hypocalcemia presumably due to the increased insult to the parathyroids from combined bilateral thyroidectomy and parathyroidectomy. More consecutive thyroidectomy, along with parathyroid autotransplantation when indicated, will provide definitive treatment of the thyroid cancer and at the same time minimize the risk of postoperative hypoparathyroidism.