Only 49 % of diminutive colorectal polyps are neoplastic, but a tiny percentage contains advanced histology. We aimed to determine the rate of advanced diminutive polyps and to evaluate the influence of age, gender, number, and localization. Patients undergoing a videocolonoscopy in October 2010 and April 2012 were collected prospectively. Subjects with polyps ≤5 mm in diameter were recruited into the study. The presence of a villous component of >25 % and a high degree of dysplasia were categorized as polyps with advanced histology. Two hundred eight diminutive polyps were identified in 102 patients. Twenty (9.6 %) diminutive polyps in 13 (12.74 %) patients showed advanced histology. The probability of having an advanced diminutive polyp was higher in patients who have more than one polyp or have polyps localized all along the colon or only to the distal part (p < 0.001 and p = 0.002). Having more than one polyp increases the likelihood of having advanced diminutive polyp according to a multivariate analysis (p = 0.003). Polyps accompanying any dysplastic diminutive polyp, being one of multiple polyps, and distributed all along the colon or localized to only the distal part have an increased probability of being an advanced diminutive polyp (p < 0.001, p = 0.047, p < 0.001, and p = 0.008). Multivariate logistic regression demonstrated that only any accompanying dysplastic diminutive polyp increases the probability of a polyp being advanced diminutive (p = 0.034). Diminutive polyps could have advanced histology. Multiple polyps located in the whole colorectum or to the distal part or accompanying any advanced polyps may harbor an advanced histology and should be removed.
Keywords: Advanced histology; Colonoscopy; Colorectal polyps; Diminutive.