Primary hyperparathyroidism occurs as a result of isolated
parathyroid adenoma in 80% to 85% of all cases. A (
99m)technetium ((99m)Tc) sestamibi scan or neck ultrasonography is used to localize the
neoplasm prior to surgical intervention. A 53-year-old female was referred for the exclusion of
metabolic bone disease. She presented with
low back pain that had persisted for the past 6 months and elevated serum
alkaline phosphatase (1,253 IU/L). Four years previously, she had been diagnosed at a local hospital with a 2.3-cm
thyroid nodule, which was determined to be pathologically benign.
Radiofrequency ablation was performed at the same hospital because the nodule was still growing during the follow-up period 2 years before the visit to our hospital, and the procedure was unsuccessful in reducing the size of the nodule. The results of the laboratory tests in our hospital were as follows: serum
calcium, 14.6 mg/dL;
phosphorus, 3.5 mg/dL; and intact
parathyroid hormone (iPTH), 1,911 pg/mL. Neck ultrasonography and (99m)Tc sestamibi scan detected a 5-cm
parathyroid neoplasm in the left lower lobe of the patient's thyroid; left
parathyroidectomy was performed. This case indicated that thyroid ultrasonographers and pathologists need to be experienced enough to differentiate a
parathyroid neoplasm from a
thyroid nodule; (99m)Tc sestamibi scan, serum
calcium, and iPTH levels can help to establish the diagnosis of
parathyroid neoplasm.