Diagnostic role of combined chromo- and zoom colonoscopy in asymptomatic patients with genetic predisposition of familiar adenomatosus polyposis syndrome

Abstract

Introduction: Combined chromo- and zoom colonoscopy is proposed to improve the detection efficacy of small colorectal polyps and to differentiate between hyperplastic, adenomatosus and dysplastic polyps. The aim of the present study was to investigate young, asymptomatic but genetically predisposed members of FAP families by means of chromo- and zoom colonoscopy. Methods: During the year of 2005, we performed chromo- and zoom colonoscopy in three individuals (3 female, mean age: 27 years), all were genetically predisposed to FAP. Colonoscopy was performed with the Olympus zoom colonoscopy (CZ- 160i). Each 20cm long segments of the colon was first investigated natively, then methylen blue was injected through a washing pipe and the same segment was investigated with 2–5x zoom magnification. All examination period was continuously recorded to DVD. Results: The average investigation time was 45min. Small adenomatosus polyps were detected in all three patients; one of them had negative colonoscopy in a year before. During zoom colonoscopy 36 small colonic polyps were detected, magnified and then removed by biopsy. Histological examinations demonstrated 6 hyperplastic polyps, 30 adenomatosus polyps, out of which had 27 minimal and 3 moderate dysplasia. According to the analysis of video pictures, combined chromo and zoom colonoscopy detected significantly more polyps then routine colonoscopy. Differentiation between hyperplastic and adenomatosus polyps was also attempted. Conclusion: Combined chromo and zoom colonoscopy is a useful method for the early diagnosis of FAP in genetically predisposed but asymptomatic young members of FAP families