Adenomatous colonic polyps are rare in ulcerative colitis

BACKGROUND: Uncertainty exists as to whether dysplastic polyps in ulcerative colitis should always be managed as dysplasia-associated lesions/masses requiring colectomy, or whether some can be managed by polypectomy. The prevalence of non-inflammatory polyps in ulcerative colitis is unknown. AIM: To compare dysplastic polyp occurrence in patients with ulcerative colitis and in patients without inflammatory bowel disease. METHODS: The clinical, endoscopic and histological records of 150 ulcerative colitis patients (median disease duration, 10 years; 57% with pancolitis) undergoing colonoscopy were scrutinized for any polyp history. Two hundred and five patients undergoing colonoscopy for altered bowel habit, but without features suggestive of polyp presence, were used as a control group. Immunohistochemical staining of flat and polypoid mucosa for p16, beta-catenin, p53 and cyclo-oxygenase-2 was compared in the two groups. RESULTS: Only six (4%) ulcerative colitis patients had ever had dysplastic polyps. Two had single adenomatous polyps proximal to the colitis segment. Of the four patients with dysplastic polyps within colitic mucosa, two were treated endoscopically, but in two the lesions were considered to be dysplasia-associated lesions/masses and colectomy was advised. In contrast, 24 controls had at least one adenomatous polyp (chi(2) = 6.7, P < 0.01). Ten (6.7%) ulcerative colitis patients and 24 (12%) control patients had metaplastic polyps (N.S.). Immunohistochemical staining was not discriminatory. CONCLUSION: Despite the increased cancer risk in long-standing ulcerative colitis, adenomatous polyps arise less frequently in ulcerative colitis patients than in patients without ulcerative colitis.