Histopathologic and flow cytometric analysis of adenomatous colonic polyps.

We evaluated the histopathology, DNA content, and proliferative activity of colonic polyps independently. Paraffin-embedded specimens were used as source material. In each case, additional sections were cut at 3 microns and stained with hematoxylin-eosin and trichrome for histopathologic analysis. For DNA analysis and measurement of proliferative activity, the polyp parts were dissected and the nonpolypoid tissue was discarded. The study was limited to those specimens that were received in our department in the years 1972 and 1977. Of the 104 polyps that were submitted for flow cytometric analysis, 36 could not be analyzed owing to excessive debris or insufficient nuclei. DNA aneuploidy was identified in 32% of the cases, with a higher value noted in larger polyps and in severely dysplastic polyps, but these values were not statistically significant. Multiple adenomas from the same patient often showed different DNA histograms. When analyzed according to the percentage of cells in S phase, no significant difference was found in proliferative activity of polyps according to DNA content or size of the polyps. These results suggest that the diagnostic significance of aneuploidy and proliferative activity in polyps must be interpreted with caution.