Serrated adenoma prevalence in inflammatory bowel disease surveillance colonoscopy, and characteristics revealed by chromoendoscopy and virtual chromoendoscopy.

BACKGROUND: Sessile or nonpolypoid neoplastic lesions, including sessile serrated adenomas (SSAs), are difficult to detect in patients with inflammatory bowel disease (IBD).
OBJECTIVES: To assess the prevalence and endoscopic features of SSA in IBD patients undergoing surveillance colonoscopy using novel endoscopic techniques.
METHODS: Histology results of biopsies from a cohort of 87 patients (47 men; median age 51.4 years; median duration of disease 16.9 years; ulcerative colitis [n=40], Crohn disease [n=43], ischemic colitis [n=4]) with longstanding colonic IBD undergoing surveillance colonoscopy were reviewed. Lesions of dysplasia (adenoma-like mass, or dysplasia-associated lesion or mass), SSAs, adenoma-like polyps, hyperplastic polyps and inflammatory polyps were identified. Surveillance colonoscopy using high-definition alone, or with iScan (Pentax, USA) dye-sprayed or virtual chromoendoscopy was performed. Lesion characteristics were described before histological diagnosis.
RESULTS: Fourteen SSAs were detected in 87 (11%) IBD patients. The endoscopic characteristics of SSA lesions were: nonpolypoid appearance (86%), predominant localization in the proximal colon (79%), >6 mm in size (79%), cloudy cover (64%), Kudo pit pattern modified type IIO (86%) and irregular spiral vascular pattern (79%). Among the 44 SSAs and hyperplastic polyps found in the present study, the above characteristics of SSA at colonoscopy had a sensitivity of 92.86% (95% CI 66.06% to 98.8%) and specificity of 93.33% (95% CI 77.89% to 98.99%) in predicting a histological diagnosis of SSA (positive predictive value 86.67%, negative predictive value 96.55%).
CONCLUSION: SSAs are a common finding at surveillance colonoscopy in IBD and have several characteristic features. Further studies are needed to evaluate the natural history of these lesions in IBD patients.