==== Front Clin EndoscClin EndoscCEClinical Endoscopy2234-24002234-2443Korean Society of Gastrointestinal Endoscopy 10.5946/ce.2018.108ce-2018-108CommentaryHow to Detect Sessile Serrated Adenoma/Polyps Kim Eun Ran http://orcid.org/0000-0001-8925-4629Chang Dong Kyung Division of Gastroenterology, Department of Internal Medicine, Sungkyunkwan University School of Medicine, Seoul, KoreaCorrespondence: Dong Kyung Chang Division of Gastroenterology, Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, Korea Tel: +82-2-3410-3409, Fax: +82-2-3410-6983, E-mail: dkchang@skku.edu7 2018 31 7 2018 51 4 313 314 23 6 2018 6 7 2018 Copyright © 2018 Korean Society of Gastrointestinal Endoscopy2018This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ==== Body See “Endoscopic Features of Mucous Cap Polyps: A Way to Predict Serrated Polyps” by Brian T. Moy, Faripour Forouhar, Chia-Ling Kuo, et al., on page 368-374. Interval colorectal cancer (CRC) is defined as CRC diagnosed after a negative screening or surveillance colonoscopy (no cancer detection) and before the next recommended follow-up examination [1]. It has been generally accepted that most CRCs are derived from adenomatous polyps. Therefore, if an adenomatous polyp is detected and removed during a regular colonoscopy, the development of CRC can be prevented. Actually, previous studies have shown that the colonoscopic removal of adenomatous polyps reduces the mortality from CRC [2]. However, interval CRCs have been consistently reported in patients who have undergone a complete colonoscopy [3,4]. There are several explanations for the development of interval CRCs including: missed lesions, new lesions, and incomplete resected lesions [5]. Recent studies have reported that interval CRCs exhibit some characteristics such as a predominant proximal location, association with the CpG island methylator phenotype (CIMP), and microsatellite instability [5,6]. Further, these characteristics of interval CRCs overlap with sessile serrated adenomas/polyps (SSA/Ps). In recent years, there has been a growing interest in SSA/Ps. Although only 20% of serrated polyps are SSA/Ps, SSA/Ps are considered more important than the other serrated polyps due to their malignant potential. SSA/Ps have been recognized as precursors of CIMP-positive and BRAF mutant CRCs that are often associated with microsatellite instability [7,8]. Unfortunately, the diagnosis of SSA/Ps is easy to miss due to their indistictive endoscopic morphologies. According to recent studies, the detection of SSA/Ps correlates with the gastroenterologist’s experience and skills [9]. Therefore, it is crucial to know about the endoscopic features of SSA/Ps. Previous studies have reported that SSA/Ps exhibit presence of several endoscopic characteristics such as a mucous cap, a rim of debris or bubbles, an alteration of the contour of a mucosal fold, the obscuring of an underlying submucosal vessel, a nodular surface and a dome-shaped protuberance [10,11]. Following analysis of 158 SSPs, Tadepalli et al. reported that a mucous cap (63.9%) and peripheral rim (51.9%) were the most common characteristics of SSPs; further, these chracteristics showed a remarkable positive association with SSPs (odds ratio [OR] 3.8, p=0.0002) [10]. Murakami et al. showed that 95%–100% of SSA/Ps with or without dysplasia had a mucous cap [12]. In a current issue of Clinical endoscopy, Moy et al. investigated whether a mucous- capped polyp, one of the most common endoscopic features of SSA/Ps, can predict the presence of serrated polyps [13]. They examined the endoscopic features of 147 mucous-capped polyps to determine if they could predict SSA/Ps. Among these, there were 127 (86%) serrated polyps (right-sided hyperplastic polyps, SSA/Ps, or traditional serrated adenomas), and only 43 (29%) SSA/Ps [13]. To find the predictive features of SSA/Ps, they also evaluated other endoscopic characteristics of mucous- capped polyps such as polyp size (≥10 mm), the distinct border, elevation, rim of debris, location, varicos vessels, nodular surface and alterations in the fold contour. It was observed that 39 polyps of 43 SSA/Ps (91%) and 56 polyps of 104 non SSA/Ps (54%) were combined with varicos vessels, and these results were found to be statistically significant (adjusted OR, 10.75; p=0.000). Based on these findings, the researchers concluded that mucous- capped polyps are more likely to be serrated polyps and the presence of a mucous cap combined with varicous vessels was a significant predictor for SSA/Ps. This study revealed some interesting results; however, these results should be interpreted with caution. Although previous studies have shown that most SSA/Ps had a mucous cap, this study demonstrated that most mucous-capped polyps were unfortunatly not SSA/Ps (43/147, 29%). Additionaly, while most mucous- capped SSA/Ps had varicous vessels (39/43, 91%), the percentage of SSA/Ps among mucous- capped polyps with varicous vessels was only 41% (39/95). Therefore, it is insufficient to conclude that the combind presence of a mucous cap and varios vessels is a predictor for SSA/Ps. Additionally, there exists a possibility that further analysis according to the number of morphological characteristics of mucous capped polyps would provide more information and better predictability for SSA/Ps. Recent studies have attempted to identify the morphological characteristics of SSA/Ps using several advanced imaging techniques such as narrow band imaging (NBI), image enhanced endoscopy or autofluorescence imaging [7,14]. According to a recent meta-analysis, most of studies conducted using NBI and NBI proved to have a higher sensitivity for detecting SSA/Ps compared to other endoscopic imaging techniques [15]. However, the sensitivity of NBI for detecting SSA/Ps has shown variations, depending on the endoscopic features. For example, indistinct borders (OR, 3.7) and a cloud-like surface (OR, 2.65) were found to be associated with SSA/Ps on high-resolution white light, whereas on an NBI, a cloud-like surface (OR, 4.91), indistinctive borders (OR, 2.38) and dark spots inside the crypts (OR, 2.05) were correlated with SSA/Ps [11]. Based on current studies, there are no clear and definite endoscopic features to predict serrated lesions, especially SSA/Ps. However, in general practice, it is paramount to make efforts not to miss the serrated polyps. This can be accomplished by gaining an in-depth knowledge of the several endoscopic characteristics of serrated polyps and conducting a meticulous examination of the bowel mucosa. Conflicts of Interest:The authors have no financial conflicts of interest. ==== Refs REFERENCES 1 Sanduleanu S le Clercq CM Dekker E Definition and taxonomy of interval colorectal cancers: a proposal for standardising nomenclature Gut 2015 64 1257 1267 25193802 2 Zauber AG Winawer SJ O’Brien MJ Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths N Engl J Med 2012 366 687 696 22356322 3 Richter JM Campbell EJ Chung DC Interval colorectal cancer after colonoscopy Clin Colorectal Cancer 2015 14 46 51 25510180 4 Brenner H Chang-Claude J Seiler CM Hoffmeister M Interval cancers after negative colonoscopy: population-based case-control study Gut 2012 61 1576 1582 22200840 5 Adler J Robertson DJ Interval colorectal cancer after colonoscopy: exploring explanations and solutions Am J Gastroenterol 2015 110 1657 1664 quiz 1665 26553207 6 Samadder NJ Curtin K Tuohy TM Characteristics of missed or interval colorectal cancer and patient survival: a population-based study Gastroenterology 2014 146 950 960 24417818 7 Tanaka Y Yamano HO Yamamoto E Endoscopic and molecular characterization of colorectal sessile serrated adenoma/polyps with cytologic dysplasia Gastrointest Endosc 2017 86 1131 1138 e4 28501592 8 Thorlacius H Takeuchi Y Kanesaka T Ljungberg O Uedo N Toth E Serrated polyps - a concealed but prevalent precursor of colorectal cancer Scand J Gastroenterol 2017 52 654 661 28277895 9 Li D Woolfrey J Jiang SF Diagnosis and predictors of sessile serrated adenoma after educational training in a large, community-based, integrated healthcare setting Gastrointest Endosc 2018 87 755 765 e1 28843582 10 Tadepalli US Feihel D Miller KM A morphologic analysis of sessile serrated polyps observed during routine colonoscopy (with video) Gastrointest Endosc 2011 74 1360 1368 22018553 11 Hazewinkel Y López-Cerón M East JE Endoscopic features of sessile serrated adenomas: validation by international experts using high-resolution white-light endoscopy and narrow-band imaging Gastrointest Endosc 2013 77 916 924 23433877 12 Murakami T Sakamoto N Ritsuno H Distinct endoscopic characteristics of sessile serrated adenoma/polyp with and without dysplasia/carcinoma Gastrointest Endosc 2017 85 590 600 27663716 13 Moy BT Forouhar F Kuo CL Devers TJ Endoscopic features of mucous cap polyps: a way to predict serrated polyps Clin Endosc 2018 51 368 374 14 Singh R Zorrón Cheng Tao Pu L Koay D Burt A Sessile serrated adenoma/polyps: where are we at in 2016? 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