Parathyroid carcinoma: a 16-year experience in a single institution

Introduction: This study aims to describe our experiences of parathyroid carcinoma. Materials and Methods: The data of clinicopathological features, surgical treatment and outcomes of seven cases of parathyroid carcinoma among 171 patients who underwent surgery for primary hyperparathyroidism over a 16-year period were analyzed. Results: The major symptoms at the diagnosis included a neck mass in three cases and multiple bone pain in five. Two patients were asymptomatic. No remarkable increases of scrum calcium levels were noted in the patients, but serum parathyroid hormone (PTH) concentrations were high in most of the patients (4 of 5 in available). A variety of imaging studies including ultrasonography, sestamibi scan, and computed tomography scan were helpful in identifying the abnormal parathyroid glands, but not specific for the diagnosis of parathyroid carcinoma. In most patients, the parathyroid carcinomas were suspected at the time of neck exploration, and confirmed by final histopathologic examinations. All patients underwent complete surgical excision with curative intent. During the follow-up period, one patient developed lung metastases 6 years later and the other one died of unrelated cause. Conclusion: Preoperative diagnosis of parathyroid carcinoma is difficult, but operative findings are helpful in the diagnosis. The optimal surgical treatment is en block radical resection including adjacent structures when parathyroid carcinoma is suspected. Unusually, although our patients presented with high serum PTH concentrations, they had normal or mild elevated scrum calcium concentrations. The reason of why should be investigated in future studies.