Parathyroid Cancer Cases: A Single Center's Experience

Objective: To review cases of parathyroid carcinoma treated at our institution during the last 30 years. Methods: We retrospectively identified patients who were treated for parathyroid carcinoma at our institution by searching for the International Classification of Diseases–Ninth Revision code. We reviewed clinical and pathologic characteristics, treatment options, disease burden and metastasis, calcium and parathyroid hormone (PTH) levels, and complications and mortality. Results: We identified 8 patients with parathyroid carcinoma between 1984 and 2014, 5 men and 3 women. Mean age at diagnosis was 50.6 years. Two patients were African American, and the rest were Caucasian. The majority were past or present smokers. The mean time to recurrence after diagnosis was 13.2 years (n = 5). Mean survival was 23.7 years for the patients who died (n = 3). Five patients had metastatic disease in the neck, spine, or lung. One patient received adjuvant radiation. Most patients had postoperative hypocalcemia due to hungry bone syndrome, but eventually hypercalcemia recurred and many required bisphosphonates and/or cinacalcet. Three patients had a history of secondary malignancies. Two patients survived over 25 years after the initial diagnosis. Conclusion: Parathyroid carcinoma is a rare malignancy. Common presentations included hypercalcemia with or without neck mass. The histologic diagnosis can be challenging. Capsular invasion and metastasis are strong pathologic evidence of carcinoma. Also, PTH more than 10 times the upper limit of normal value with severe hypercalcemia should alarm clinicians to suspect parathyroid carcinoma. Recurrence can occur many years after initial surgery, and hypercalcemia is the main cause of morbidity and mortality. Therefore, long-term follow-up is mandatory. Abbreviations: FNA = fine needle aspiration PTH = parathyroid hormone