Flow cytometric analysis of DNA content in colorectal polyps resected at endoscopy

Samples from 64 consecutive resected colorectal polyps were preserved in liquid nitrogen and analyzed by flow cytometry to assess the nuclear DNA content, which was compared to the histopathologic findings. The frequency of aneuploidy in these nonselected polyps was 17.2%. There was a significant correlation between the diameter of the polyp and the frequency of aneuploidy (P = .04), with all aneuploid polyps being greater than or equal to 10 mm. Similarly, aneuploidy was significantly more frequent for polyps that were both greater than or equal 20 mm and showed at least severe dysplasia (P = .02). On the other hand, there was no correlation between the ploidy and the gross histopathologic type (tubular, tubulovillous or villous), and the proliferation index did not correlate with any of the parameters studied.