Life-threatening hypercalcemia from a hepatocellular carcinoma secreting intact parathyroid hormone: localization by sestamibi single-photon emission computed tomographic imaging.

OBJECTIVE

To describe a patient with severe hypercalcemia and elevated intact parathyroid hormone (iPTH) levels associated with a hepatocellular carcinoma.

METHODS

We present a case report, detailing the laboratory, surgical, and sestamibi scanning findings. Moreover, the literature relating to paraneoplastic ectopic production of iPTH is reviewed.

RESULTS

A 72-year-old man had the following laboratory results at the time of initial assessment: serum calcium of 14.5 mg/dL, ionized calcium of 6.8 mg/dL, serum iPTH of 92 pg/mL, and a PTH-related peptide of <0.7 pg/mL. Findings on preoperative sestamibi scanning were suggestive of a parathyroid adenoma, with additional uptake in the dome of the liver. He was diagnosed as having primary hyperparathyroidism, and a neck exploration was undertaken. The right superior, right inferior, and left superior parathyroid glands were mildly enlarged and were excised. The left inferior parathyroid gland could not be identified, despite an extensive neck exploration. Bilateral internal jugular vein sampling demonstrated elevated iPTH levels, an indication of a systemic origin of the hormone. Postoperatively, a repeated sestamibi scan confirmed hyperactivity in the liver, and a subsequent computed tomographic scan revealed masses in segments IV, VII, and VIII of the liver in conjunction with portal vein involvement. Tissue biopsy confirmed the presence of hepatocellular carcinoma, and the fluid obtained with the biopsy specimen was strongly positive for iPTH. The patient was treated with transarterial chemoembolization but subsequently died.

CONCLUSION

This case demonstrates the rare occurrence of hepatocellular carcinoma producing iPTH as the cause of life-threatening hypercalcemia. Sestamibi scans were accurate in detecting focal hyperactivity that correlated with the malignant involvement.