The results of the clinical and the cytogenetical analysis of pseudopolyps (PP) in patients with inflammatory bowel diseases (IBD) are given in this work. In ulcerative colitis (UC) and Crohn’s disease (CD) the PP were found in different parts of the large bowel and in CD the PP are also located in terminal part of the colon. The results of our study showed not significant differences in quantity of PP in patients with UC and CD. PP of large bowel were identified in 40% of patients with IBD, who developed cancer. The karyotype of PP in the cases of IBD-related cancer were mosaical with the genomic mutation in the pathologic clones of the cells. The metaphasal plates with polyploid cell’s clones, which are found in PP, require accurate examination of the large bowel mucous for the detection of displasia and malignization area in patients with IBD. In the karyotype of PP in patients with IBD without cancer were found the multiply chromosome aberrations. Aneuploid (hypoploid) karyotypes prevailed in the mosaical clones of these patients.
