SMALL, FLAT COLORECTAL NEOPLASIAS IN LONG-STANDING ULCERATIVE-COLITISDETECTED BY HIGH-RESOLUTION ELECTRONIC VIDEO ENDOSCOPY

Background: High-resolution video endoscopy complemented with chromosc opy allows for more detailed visualization of the colonic mucosal surf ace. Methods: Using high-resolution video endoscopy and chromoscopy, w e investigated 85 patients with extensive ulcerative colitis with a di sease duration of at least 10 years who were taking part in a cancer s urveillance program. Results: In 38 of the 85 patients, 104 polyps wer e detected at endoscopy. Seventy-seven (74%) of the 104 polyps were en doscopically flat, 21 (20%) were sessile, 3 (3%) were pedunculated, an d 3 (3%) had no recorded morphology. Twenty-three (22%) polyps were ne oplastic (15 flat, 5 sessile, 2 pedunculated, 1 not recorded). Low-gra de dysplasia was found in 21 of the 23 neoplastic polyps and high-grad e dysplasia in the remaining 2 (1 flat tubular adenoma and 1 sessile v illous adenoma with invasive growth). Flat polyps were small, with a d iameter of 5 mm or less in 73% (n = 56) of cases. At histology flat po lyps revealed either flat adenomas (n = 11; 14.3%), tubular or villous structures with dysplastic cells at the lower part of the crypts (n = 4; 5.2%), flat hyperplastic polyps (n = 26; 34%), inflammatory mucosa (n = 5; 6.5%), or mucosa in remission (n = 31; 40%). Conclusion: The use of high-resolution video endoscopy complemented with chromoscopy i n ulcerative colitis enables the detection of flat neoplastic polyps. The existence of those hitherto undetected neoplasms in ulcerative col itis and their possible role in the histogenesis of colorectal cancer in ulcerative colitis deserve further investigation.