Magnifying Colonoscopy Findings for Differential Diagnosis of Sessile Serrated Adenoma/Polyps and Hyperplastic Polyps

抄録

Sessile serrated adenoma/polyps (SSA/Ps) are thought to be precursors of colorectal cancers. However, current endoscopic techniques for differentiating SSA/Ps from conventional hyperplastic polyps (HPs) have low diagnostic accuracy. The aim of the present study was to assess the ability of mucosal crypt patterns to distinguish SSA/Ps from HPs. We examined 140 lesions from 93 patients that had been diagnosed histologically as SSA/Ps or HPs at the Showa University Hospital between June 2010 and May 2012. Three experienced colonoscopists reviewed the endoscopic findings of magnifying colonoscopy. Type II open-shape (Type II-O) pit patterns and varicose microvascular vessels (VMVs) were identified according to previously proposed definitions. Although 140 lesions were initially identified for the study, 27 lesions were excluded from analysis because of insufficient endoscopic findings. Thus, endoscopic findings from a total of 113 lesions (68 SSA/Ps and 45 HPs) were evaluated. Of 113 serrated polyps, 51 lesions (44 SSA/Ps and 7 HPs; P<0.01) had Type II-O pit patterns. The inter- and intra-observer agreement for these patterns among three colonoscopists was κ=0.61 (range 0.57–0.65) and κ=0.68 (range 0.52–0.94), respectively. The positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity of Type II-O pit patterns for differentiating between SSA/P and HP were 86%, 61%, 65%, and 84%, respectively. In contrast, the PPV, NPV, sensitivity, and specificity of VMVs were 68%, 43%, 37%, and 73%, respectively. The results indicate that Type II-O mucosal crypt patterns may be useful for the differential diagnosis of SSAPs and HPs.