A new formula for predicting the actual volume of parathyroid adenoma in patients with primary hyperparathyroidism

Knowing adenoma volume in patients with primary hyperparathyroidism is useful for surgeons during parathyroidectomy. The primary aim of our study was to identify the most accurate method for calculating adenoma volume. Our secondary aim was to determine the relationship between adenoma volume and preoperative biochemical parameters (parathyroid hormone [PTH] and calcium levels).

The medical histories of 75 patients who underwent surgery for a single parathyroid adenoma were prospectively collected. After excision, the adenomas were placed in water-filled syringes, and their actual volume was determined according to the amount of water displaced. The radiological volume of the adenomas was calculated using the ellipsoid body formula according to the ultrasonographic dimensions. The PTH and calcium levels of the patients were retrieved from the patients' hospital records.

The calculated radiological volumes correlated with the actual adenoma volumes, but there were significant differences between the two measurements. A new formula was developed based on actual volumes and radiological volumes. A positive correlation was found between the adenoma volumes and the preoperative PTH and calcium levels.

Adenoma volume calculated using a mathematical formula based on ultrasound measurements does not accurately reflect the actual volume. Higher preoperative calcium and PTH levels are associated with larger adenoma size.