DNA content by image analysis. An accurate discriminator of malignancy in pericardial effusions

DNA analysis was performed on 20 cytologically equivocal pericardial effusions to determine if it would be a useful ancillary technique in identifying malignancy. Ploidy determination by interactive image analysis showed single diploid DNA peaks, with no cells > 5c, in all eight reactive cases studied. The reactive cases had a mean proliferation index of 1.3. All 12 malignant cases studied had cells with DNA content > 5c. A dominant DNA peak at 2c was present in 25%, dominant aneuploid stem lines were present in 25%, and multiple stem lines were present in 50% of the malignant cases. By image analysis, the presence of DNA content > 5c was both sensitive and specific for detecting malignancy in the group of pericardial effusions evaluated.