Synchronous parathyroid carcinoma and papillary thyroid carcinoma

Abstract The simultaneous occurrence of parathyroid carcinoma and nonmedullary thyroid carcinoma is unusual. We report the case of 60‐year‐old woman who was found to have concurrent parathyroid carcinoma with severe clinical manifestations of primary hyperparthyroidism in addition to an incidental papillary thyroid carcinoma. Parathyroid hormone level was 569 pg/ml (normal range 10–65), and the serum calcium concentration was 13.83 mg/dl (normal range, 8.8–10.4). Preoperative investigation found a large 3 cm anterior cervical nodule suggestive of parathyroid adenoma. Total thyroidectomy and left parathyroidectomy were performed, and the final anatomopathological examination of the operative specimen concluded the coexistence of papillary microcarcinoma and parathyroid carcinoma. Although parathyroid carcinoma is an uncommon cause of hypercalcemia, it should be considered when severe hypercalcemia is observed, and in case of coexistence of thyroid nodules. The possibility of both malignancies must also be considered since parathyroid and nonmedullary thyroid carcinoma rare cases have previously been reported.