A rare coexistence of parathyroid adenoma and medullary and papillary thyroid carcinoma.

The combination of parathyroid adenoma, medullary thyroid carcinoma (MTC), and papillary thyroid carcinoma (PTC) has been reported occasionally, but it has now been recognized more often through effective evaluations. However, the etiology and risk factors remain unclear, so we discuss them in this article. Here, we report the case of a 64-year-old woman with parathyroid adenoma, MTC, and PTC diagnosed incidentally. This woman was admitted to the Xingtai People's Hospital affiliated to Hebei Medical University for an apparently aggravating symptom of hypodynamia. Her past medical history included diabetes and a left nephrolith. Upon admission, her bloodwork showed hypercalcemia, hypophosphatemia, and elevated serum parathyroid hormone. Subsequently, the sonographic findings revealed dominant nodules in both the right and left lobes with a left inferior suspected parathyroid adenoma. The patient underwent fine needle aspiration (FNA) of the bilateral thyroid lobes, the results of which were both thyroid carcinoma. Therefore, a thyroidectomy, a neck dissection, and the excision of a suspected parathyroid adenoma were performed. A histological examination revealed a combination of parathyroid adenoma, MTC, and PTC. Her serum calcium and parathyroid hormone levels returned to the normal range after the surgery. Our case highlighted the fact that even though the concurrent existence of parathyroid adenoma, MTC, and PTC is rare, the diagnosis of this coexistence should be considered in primary hyperparathyroidism (PHPT). To avoid repeat surgeries, patients with coexisting diseases should be screened cautiously. Therefore, we recommend a preoperative check of the calcium levels in patients with thyroid cancer and a preoperative thyroid check in all patients with PHPT.