Hyperfunctioning intrathyroid parathyroid adenoma: report of two cases.

We report herein two cases of intrathyroid parathyroid adenoma, which is a rare condition in patients with hyperparathyroidism. In the first patient, an excised intrathyroid nodule was diagnosed to be parathyroid adenoma postoperatively. In the second patient, preoperative localization studies suggested the possibility of an intrathyroid adenoma. When a pathological gland is not found during surgery for primary hyperparathyroidism, an ectopic parathyroid gland including an intrathyroid adenoma should thus be considered.