DNA aneuploidy in adenomas of endocrine organs

The nuclear DNA content of 44 pituitary, 49 thyroid, 54 parathyroid, and 17 adrenal adenomas was analyzed from paraffin-embedded tissue with flow cytometry. Interpretable histograms of good quality (CV less than 7%, mean CV, 4%) were obtained in 96% of the cases. Unequivocal evidence of DNA aneuploidy was found in 29% of pituitary, 25% of thyroid, 35% of parathyroid, and in 53% of adrenal adenomas. Excluding the multiploid (N = 2) and tetraploid adenomas (N = 5), the DNA indices of aneuploid adenomas were generally small (mean, 1.34). Patients with a diploid thyroid or parathyroid adenoma had a lower mean age at diagnosis than patients with a nondiploid adenoma. None of the adenomas gave rise to metastases after conservative surgery. It is concluded that DNA aneuploidy is common in endocrine adenomas and that the presence of DNA aneuploidy is not incompatible with a benign histologic diagnosis. The usefulness of DNA aneuploidy as a conclusive sign of malignancy in clinical practice is questioned.