DNA histogram of parathyroid tissue in determining extent of parathyroidectomy.

In an attempt to better define hyperplasia from adenoma and for more accurate discernment of grossly normal but histologically abnormal presumed hyperfunctioning gland, parathyroid tissue obtained at operation was subjected to flow cytometric analysis producing DNA histogram. Seventeen abnormal specimens and seven normal specimens obtained from parathyroidectomy cases were placed in RPMI 1640 culture medium, treated to produce a monodispersed cell suspension, and stained with propidium iodide fluorescent dye to provide a measure of DNA content that could be graphically demonstrated. All cell cycles for affected cell populations could be demonstrated on DNA histogram in the G0G1, S, and G2M phases. Proliferative index was arbitrarily derived by combining percentages of G2M plus S phases. It was apparent that the value so derived showed a tendency for higher value for the abnormal parathyroid tissue but the overlap was sufficient so that no specific discriminating value could be placed on DNA histogram. While flow cytometry may not be of significant use in intraoperative identification of abnormal parathyroid tissue, the values obtained may indicate that a spectrum of activity occurs in hyperparathyroidism that cannot be fully appreciated at the present time and that may in the light of incomplete knowledge manifest itself in the clinical state of hyperparathyroidism and hypercalcemia. The findings of our flow cytometry study may indeed lend credence to the view that all hyperparathyroidism represents a four-gland hyperfunction although this does not support as a consequence routine subtotal parathyroidectomy but should stimulate further inquiry into the pathogenesis of primary hyperparathyroidism.