Tc99m-sestamibi scintigraphy and cell proliferation in primary hyperparathyroidism: a causal or casual relationship?

Sestamibi scintigraphy has become the fundamental technique for preoperative location of hyperfunctioning glands responsible for hyperparathyroidism, especially in the case of adenomas. However, little is known about the mechanisms of tracer uptake and retention by these glands, mechanisms that have been related to an increased gland metabolism. Our goal was to determine whether there is a relationship between the positive result of gammagraphy with sestamibi, for diagnosing the location of parathyroid adenomas, and the cell proliferation index.

Six glands corresponding to sestamibi false negatives and 12 true positives were studied in patients with single-adenoma primary hyperparathyroidism. The following data were recorded in all the patients: age, gender, clinical and analytical data, gland weight, and parathyroid hormone (PTH)/gland weight ratio. An immunohistochemical study of the glands was also done with the use of Ki67, with determination of the mean proliferation index of each group for comparison purposes.

On comparing the 2 groups, we found no differences between the clinical or analytical parameters. Differences were found only for proliferation index-(5.7% in true positive glands versus 0.3% in false negative glands (P <.004).

Tracer (sestamibi) uptake by hyperfunctioning parathyroid adenomas in primary hyperparathyroidism might be linked to a higher gland metabolism activity, probably related to cell proliferation.