Screening for dysplasia and TP53 mutations in closed rectal stumps of patients with ulcerative colitis or Crohn disease.

Background: Patients who undergo colectomy due to intractable chronic inflammatory bowel disease (IBD) may keep a closed rectal stump for several years, which may be at increased risk of malignant transformation owing to residual inflammatory activity. We examined a hospital series of patients with ulcerative colitis or Crohn colitis to describe the clinical, endoscopical and histological features of the closed rectal stump and to screen for dysplasia and mutations in the TP53 tumour suppressor gene. Methods: During rigid proctoscopy, rectal mucosal biopsy specimens and rectal lavage fluid were collected from 42 patients. Biopsy specimens were examined histologically, and genomic DNA extracted from frozen biopsies and lavage fluid was analysed for mutations in TP53 exons 4–9. Results: The median disease duration was 8.5 years (range 1.3–34 years). No endoscopic or histological signs of dysplasia or carcinoma were seen and no mutations in the TP53 gene were detected in any biopsy or lavage fluid specimens....