Multiple synchronous colorectal carcinomas: a ploidy study by image analysis.

Cytometry could represent an ancillary technique to morphology in order to understand whether multiple synchronous colorectal carcinomas arose independently. Twenty-eight multiple synchronous tumours, assessed by means of a computerized image analysis system for DNA ploidy, were categorized as diploid (4) or not diploid (24). The ploidy classes were: DNA-diploid, DNA-tetraploid, and DNA-aneuploid. The DNA Index (DI) ranged from 0,90 to 2,66. The overall concordance rate for ploidy and DI class with synchronous tumours was 69% and 31%, respectively. The high concordance rate in ploidic categories suggests the metastatic origin of our multiple synchronous tumours. Moreover, they showed site, Dukes' classification, degree of differentiation, percentage of ploidy class, and DI distribution comparable to the single colorectal carcinomas. In conclusion, image analysis is a reliable technique to determine the independent clonality or the common origin of multiple colorectal tumours when the evaluation based on the simple histopathological criteria is not satisfactory.