INCREASED SERUM CALCITONIN IN SPORADIC PRIMARY HYPERPARATHYROIDISM IS AN UNCOMMON OCCURRENCE.

Objective: To evaluate calcitonin (CT) levels in sporadic primary hyperparathyroidism (PHPT), which has to date rarely been considered. Methods: We evaluated serum CT levels in 290 consecutive patients with sporadic PHPT at diagnosis. Results: Mild elevations in CT levels (hyperCT) were found in 25 patients (8.6%), with no correlation among the demographic, clinical, and biochemical findings. In addition, no differences were found between patients with and without hyperCT. Follow-up data were available for 19/25 patients, but CT values were only available for 10. CT normalized in all surgically cured patients regardless of the extent of the surgery (parathyroidectomy [PTX] only in 8 and associated with partial or total thyroidectomy for benign nodular goiters in 7). Conclusion: hyperCT is an uncommon feature of sporadic PHPT and not related to biochemical or clinical features of the disease. In addition, hyperCT is reversible after PTX, regardless of whether concomitant thyroidectomies have been conducted. Abbreviations: CT = calcitonin; eGFR = estimated glomerular filtration rate; hyperCT = hypercalcitoninemia; MEN = multiple endocrine neoplasm; MTC = medullary thyroid carcinoma; PHPT = primary hyperparathyroidism; PPI = proton pump inhibitor; PTH = parathyroid hormone; PTX = parathyroidectomy.