HYPERCALCEMIA CAUSED BY ECTOPIC PRODUCTION OF PARATHYROID-HORMONE IN A PATIENT WITH PAPILLARY ADENOCARCINOMA OF THE THYROID-GLAND

Hypercalcemia and elevation of a serum PTH level 9800 pg/mL (normal: 1 60-520) were found in a 72-yr-old woman who had a lung cancer. She und erwent pulmonary lobectomy for a suspected PTH producing lung cancer. However, hypercalcemia and elevation of the serum PTH level were persi stent postoperatively. Subsequent examination, using parathyroid scint iscanning, revealed a hot spot in the right lower part of the thyroid gland, suggesting hypercalcemia caused by a parathyroid tumor. She und erwent bilateral exploration of the neck; however, four apparently nor mal parathyroid glands were seen. Therefore, hemithyroidectomy was per formed for the possibility of an intrathyroidal parathyroid adenoma. S erum calcium and PTH levels declined after this operation. A nodular l esion was found in the cut sections of the resected specimen, which wa s consistent with the result of the scintiscanning. Histological exami nations revealed a papillary adenocarcinoma of the thyroid gland, and the PTH-immunoreactivity in the tumor cells was confirmed. These findi ngs strongly suggest that PTH could be produced ectopically by the pap illary adenocarcinoma of the thyroid gland.