Synchronous parathyroid and papillary thyroid carcinoma.

Concomitant thyroid disease is not unusual among patients with primary hyperparathyroidism. However, the simultaneous occurrence of parathyroid and thyroid carcinoma is extremely rare. We report a 38-year-old man with primary hyperparathyroidism who presented with osteitis fibrosa cystica complicated with pathologic femoral neck fracture. Preoperative investigation for exclusion of multiple endocrine neoplasia did not find evidence of medullary thyroid carcinoma or pheochromocytoma, but imaging studies revealed the presence of nodules in the right lobe and a parathyroid lesion over the left inferior pole of the thyroid gland. Total thyroidectomy, left parathyroidectomy, and bipolar hemiarthroplasty of the left hip were then performed simultaneously. The resected specimens were pathologically identified as papillary thyroid carcinoma and parathyroid carcinoma, respectively. After the operation, 131I ablation therapy was administered at a dose of 120 mCi. Additional doses of 30 mCi were given yearly as serum thyroglobulin level became elevated. Serum calcium level remained normal during yearly follow-up. Although parathyroid carcinoma is an uncommon cause of parathyroid hormone-dependent hypercalcemia, it should nonetheless be given due consideration because its surgical approach differs from that of parathyroid adenoma. As the coexistence of parathyroid and non-medullary thyroid carcinoma has previously been reported, the possibility of both malignancies must also be considered in the setting of primary hyperparathyroidism with thyroid nodules. If confirmed with preoperative parathyroid scintigraphic and other laboratory studies, an optimal outcome may be achieved with complete resection of both tumors at the time of initial operation, followed by adjunctive therapy.