Weight of Normal Parathyroid Glands in Patients with Parathyroid Adenomas

Although the size and weight of a parathyroid gland are frequently the only intraoperative determinants of abnormality, these parameters have not been examined in living patients with primary hyperparathyroidism (PHP). The records of 240 patients who underwent parathyroidectomy according to standard surgical practice by a single surgeon were reviewed to identify those who were euparathyroid after in toto removal of a histologically confirmed normal gland and a histologically confirmed adenoma. The 25 (86%) females and 4 (14%) males who met the study criteria had a mean age of 60 yr (range, 33-82 yr). The mean PTH level was 130.1 pg/ml (range, 58-278) before parathyroidectomy and 32.4 pg/ml (range, 1-68) after parathyroidectomy. The mean calcium level was 11.1 mg/dl (range, 10-14) before and 8.7 mg/dl (range, 8-10) after parathyroidectomy. Thirty-four intact normal glands were removed and available for analysis. Their mean weight was 62.4 +/- 31.6 mg (range, 18-161 mg), and 15 (44%) weighed 60 mg or more. The mean weight of the adenomas was 553.7 +/- 520.5 mg (range, 66-2536). Adenomas were clearly distinguished from normal glands by cellularity, stromal fat, and intracellular fat in chief cells. The weight of normal parathyroid glands removed at surgery in patients with PHP may be greater than that reported in autopsy studies. Therefore, certain histological features are a better measure than weight in determining whether a gland is normal, and intraoperative identification of slightly enlarged glands should not lead to immediate subtotal parathyroidectomy.