Secondary hyperparathyroidism and thyroid cancer.

To the best of our knowledge this is the first report of two cases with concomitant secondary hyperparathyroidism and thyroid cancer. Despite previously published reports of a possible association between primary hyperparathyroidism and non-medullary thyroid cancer, we believe that such an association is coincidental. Nevertheless, increased awareness of the possibility of encountering and treating both diseases at the same time is advisable.