An ectopic parathyroid adenoma revealed by L-thyroxine side effect on bone. Case report.

Hyperparathyroidism due to an ectopic parathyroid adenoma commonly is revealed by parathyroid hormone (PTH) high serum level and its clinical effects on bone loss. We report a case in which exogenous L-thyroxine side effect on bone in the treatment of thyroid solitary nodule disease produced bone loss in a patient with subclinical hyperparathyroidism due to an ectopic parathyroid adenoma. Our case report suggests the importance of monitoring both clinical symptomatology and calcium and phosphorous serum levels as routine lab investigation in all patients who receive L-thyroxine treatment.