Clinical, biochemical, and pathologic features of radiation-associated hyperparathyroidism.

The clinical, biochemical, and pathologic findings in 43 patients with primary hyperparathyroidism (HPT) and a history of irradiation to the head or neck were compared with those found in a group of 162 patients with HPT without prior irradiation. There were no differences between the groups with regard to mean age at the time of diagnosis, male to female ratio, serum calcium, phosphorus, and parathyroid hormone concentrations; in the frequency of single parathyroid adenomas v multiglandular disease; or in associated nonthyroidal neoplasms. Asymptomatic HPT was found with greater frequency in the irradiated patients. Almost 80% of the patients with a history of irradiation had concomitant thyroid disease, primarily adenomas and carcinomas, while less than 50% of the patients without a history of irradiation had thyroid disease, mainly colloid nodules, at surgery.