Hypercalcemia in metastatic parathyroid carcinoma followed by hypocalcemia after resection: A case report

A 72‐year‐old man was diagnosed with hypercalcaemia 13 years ago. He was diagnosed with hyperparathyroidism associated with a parathyroid tumour and surgery was performed. Postoperatively, his serum calcium levels, which had once normalized, rose again. Medical treatment for hypercalcaemia failed to control the condition. A chest computed tomography showed multiple pulmonary nodules which were diagnosed as pulmonary metastases of parathyroid carcinoma. The tumour was considered to be the cause of the hypercalcaemia and volume reduction surgery was performed. Immediately after surgery, the patient presented with hypocalcaemia and required calcium correction with Calcium Gluconate Hydrate. Since then, the serum calcium level has stabilized and the patient has progressed without medical treatment. Parathyroid carcinoma is rare. This is a valuable case in which the serum calcium level was controlled by surgery. The patient also developed post‐operative hypocalcaemia, which should be reported.