Relationship of Parathyroid Adenoma Volume and Biochemical Function

Abstract

We retrospectively studied data of 24 patients with surgically proven hyperparathyroidism to determine whether biochemical function correlated with the calculated volume of parathyroid adenoma. Carboxyl-terminal parathyroid hormone (C-PTH), amino-terminal parathyroid hormone (N-PTH), nephrogenous cyclic AMP (N-CAMP), and other markers of calcium metabolism were measured with standard techniques. Tumors were divided into small ( < 1.0 cm³) or large (≧1.0 cm³) sizes. N-PTH and C-PTH measurements were increased in 10% and 30% of patients with small tumors and in 71 and 78% of patients with large tumors. Serum calcium, N-CAMP, C-PTH and N-PTH tended to be greater with large tumors, but only C-PTH was significant. We concluded that the size of parathyroid adenoma influenced biochemical measurements of its activity and that the measurements of PTH in patients with small tumors are not as sensitive as those in patients with large tumors.

Primary hyperparathyroidism: do perioperative biochemical variables correlate with parathyroid adenoma weight or volume?

“…A number of previous studies have attempted to quantify the relationship between the biochemical markers of hyperparathyroidism and parathyroid adenoma size and volume with mixed results. A literature search revealed eight previous studies comparing size of adenomas to preoperative calcium or parathyroid hormone levels 7–14 …”

“…Rutledge et al 7 found a statistically significant but weak correlation ( r = 0.16; Pearson's coefficient) between adenoma weight and preoperative [Ca] and [PTH], while Dubost, 8 Wagner, 9 Saadeh 10 and Williams 11 found no relationship between serum calcium and PTH levels and adenoma weight or volume, although these studies did not specifically exclude patients with parathyroid hyperplasia, double adenomas, renal hyperparathyroidism, and parathyroid carcinoma. A recent study of 63 single adenomas by Bindlish et al.…”

“…It is not clear if the normal glands entirely cease secretion of PTH and, if so, at which stage in the disease process this occurs. Therefore, in patients undergoing surgery for primary hyperparathyroidism, the level of PTH is a function of at least two variables: the parathyroid adenoma PTH output, which may have a variable relationship to adenoma weight, 10 as well as changes in PTH output of the normal parathyroid glands. The relationship between adenoma size and [Ca] is even more complex, since [Ca] is determined not only by [PTH], but a host of short and long‐acting endocrine mechanisms which include calcitonin and 1–25‐dihydroxycholecalciferol 17 .…”

“…A literature search revealed eight previous studies comparing size of adenomas to preoperative calcium or parathyroid hormone levels. [7][8][9][10][11][12][13][14] Rutledge et al 7 found a statistically significant but weak correlation (r ¼ 0.16; Pearson's coefficient) between adenoma weight and preoperative [Ca] and [PTH], while Dubost, 8 Wagner, 9 Saadeh 10 and Williams 11 found no relationship between serum calcium and PTH levels and adenoma weight or volume, although these studies did not specifically exclude patients with parathyroid hyperplasia, double adenomas, renal hyperparathyroidism, and parathyroid carcinoma. A recent study of 63 single adenomas by Bindlish et al 12 demonstrated statistically significant correlations between preoperative serum calcium and PTH with adenoma weight (P ¼ 0.001).…”

“…It is not clear if the normal glands entirely cease secretion of PTH and, if so, at which stage in the disease process this occurs. Therefore, in patients undergoing surgery for primary hyperparathyroidism, the level of PTH is a function of at least two variables: the parathyroid adenoma PTH output, which may have a variable relationship to adenoma weight, 10 Primary hyperparathyroidism 183 but a host of short and long-acting endocrine mechanisms which include calcitonin and 1-25-dihydroxycholecalciferol. 17 It was not possible in this study to predict postoperative hypocalcaemia using clinical, biochemical or pathological variables.…”