Occurrence of previous neck radiotherapy among patients with associated non-medullary thyroid carcinoma and parathyroid adenoma or hyperplasia.

Sixteen consecutive patients with co-existent non-medullary thyroid carcinoma and parathyroid adenoma or hyperplasia are reported. Ten of these patients had earlier been treated with external radiation in the neck region. The estimated absorbed dose varied between 5 and 23 gray. The diagnosis of thyroid carcinoma and hyperparathyroidism (HPT) was established 36 years (average) after exposure to radiation. The findings are in accordance with the hypothesis that radiation can serve as an etiological factor in the development of associated thyroid carcinoma and HPT.