Retrospective analysis of primary hyperparathyroidism combined with papillary thyroid carcinoma

Objective To evaluate the differences of the malignant rate of thyroid nodules between primary hyperparathyroidism (PHPT) patients and health examination population, and analyze the clinical characteristics of PHPT combined with papillary thyroid carcinoma (PTC). Methods The clinical data of 158 PHPT patients who had underwent parathyroidectomy and 468 thyroid nodule patients who had underwent fine-needle aspiration (FNA) from 2009 to 2014 were retrospectively analyzed, and the detection rate of PTC in patients with thyroid nodule was recorded. Results Of the 158 patients with PHPT, 61 patients had thyroid nodules, the incidence of PHPT with thyroid nodule was 38.6% (61/158), and postoperative pathologically proved PTC was in 12 cases (19.7%). Of the 468 thyroid nodule patients who had underwent FNA, postoperative pathologically proved PTC was in 19 patients (4.1%). The malignant rate of thyroid nodules in PHPT patients was significantly higher than that in health examination population (P < 0.01). The adjusted serum calcium in patients with PHPT combined with PCT was significantly lower than that in patients with PHPT combined with benign thyroid nodules and patients with PHPT without thyroid nodules: (2.63 ± 0.26) mmol/L vs. (2.92 ± 0.32) and (2.93 ± 0.47) mmol/L, and there was statistical difference (P<0.05). Conclusions The malignant rate of thyroid nodules in PHPT patients is significantly higher than that in patients from health examination population, which suggests that PHPT might be a risk factor for the malignancy of thyroid nodules. A lower level of serum calcium may predict the existence of PCT in PHPT patients with thyroid nodules. Key words: Hyperparathyroidism, primary; Thyroid neoplasms; Carcinoma, papillary