DNA analysis and parathyroid pathology.

The nuclear DNA content of 85 parathyroid glands (4 carcinomas, 39 adenomas, 21 secondary parathyroid hyperplasias, and 21 normal parathyroid glands) were determined by flow cytometric analysis. All normal parathyroid glands, 85% of the adenomas, and 83.3% of the secondary hyperplastic glands had DNA indices within values of 0.85-1.1. Paraffin-embedded fixed glands showed less DNA staining than that found with fresh or normal glands. Glands from patients with carcinoma showed DNA indices outside the normal DNA index range. When the percent of nuclei within the G0/G1 phase of the cell cycle was compared between the study groups, highly significant results were found. While patients with secondary hyperplasia showed a similar distribution to the normal glands studied, only 48% of primary adenomas showed over 80% of cells within the G0/G1 region. A clear subgroup of adenomas was defined with more rapidly cycling tetraploid cells, and showing classical adenoma pathology. This group showed negative correlation with gland weight, plasma calcium, and ionized calcium. These findings suggested that a different etiology of the disease process occurs between secondary hyperplasia and parathyroid adenoma. Such abnormal adenomas may form a group worthy of long-term follow-up.