Flow Cytometry of Fetal Adrenal Glands with Adrenocortical Cytomegaly

Adrenal glands from four autopsied fetuses of 18 to 36 weeks gestation showed varying degrees of cortical cytomegaly. Formalin'fixed, paraffin-embedded sections from these four pairs of glands were studied by flow cytometry to analyze their DNA content and cell cycle parameters. Flow cytometry of Case 1, which had diffuse bilateral cytomegaly, demonstrated a major diploid peak, an increased percentage of tetraploid cells, and a decrease in S phase compared to an age-matched control with no evidence of cytomegaly (Case 2). Cases 3, 4, and 5 showed focal and/or unilateral adrenocortical cytomegaly and were diploid by flow cytometry with no differences in synthetic or tetraploid fractions compared to the control tissues. The focal distribution of the lesions or the limits of resolution of the instrumentation could account for some of these results. However, the findings in Case 1 suggest that the cytomegalic cells are tetraploid in DNA content and may have decreased DNA synthetic activity. A current hypothesis that these cells have undergone a period of sustained hyperactivity followed by exhaustion in reaction to an unknown stimulus is supported by our observations.