Original Article
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Aug 28, 2012; 18(32): 4308-4316
Published online Aug 28, 2012. doi: 10.3748/wjg.v18.i32.4308
Evaluation of magnifying colonoscopy in the diagnosis of serrated polyps
Shinya Ishigooka, Masahito Nomoto, Nobuyuki Obinata, Yoshichika Oishi, Yoshinori Sato, Satoko Nakatsu, Midori Suzuki, Yoshiko Ikeda, Tadateru Maehata, Tomoaki Kimura, Yoshiyuki Watanabe, Takashi Nakajima, Hiro-o Yamano, Hiroshi Yasuda, Fumio Itoh
Shinya Ishigooka, Masahito Nomoto, Yoshinori Sato, Satoko Nakatsu, Midori Suzuki, Yoshiko Ikeda, Tadateru Maehata, Yoshiyuki Watanabe, Hiroshi Yasuda, Fumio Itoh, Department of Internal Medicine, Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan
Nobuyuki Obinata, Yoshichika Oishi, Takashi Nakajima, Center of Gastroenterology, St. Marianna Toyoko Hospital, Kawasaki 211-0063, Japan
Tomoaki Kimura, Hiro-o Yamano, Department of Gastroenterology, Akita Red Cross Hospital, Akita 010-1495, Japan
Author contributions: Ishigooka S and Watanabe Y contributed equally to this work; Ishigooka S, Watanabe Y, Nomoto M, Obinata N, Oishi Y, Sato Y, Nakatsu S, Suzuki M, Ikeda Y, Maehata T and Nakajima T designed this study; Ishigooka S, Watanabe Y, Kimura T, Yamano H, Yasuda H and Itoh F analyzed all data; and Ishigooka S and Watanabe Y wrote the paper.
Supported by The Japanese Foundation for Research and Promotion of Endoscopy (JFE), in part; The Japanese Society of Gastroenterology (JSGE), to Watanabe Y; The Princess Takamatsu Cancer Research Fund; and A Generous Gift from both the JFE and the JSGE
Correspondence to: Yoshiyuki Watanabe, MD, PhD, Department of Internal Medicine, Division of Gastroenterology and Hepatology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamaeku, Kawasaki, Kanagawa 216-8511, Japan. ponponta@marianna-u.ac.jp
Telephone: +81-44-9778111 Fax: +81-44-9765805
Received: June 13, 2012
Revised: August 16, 2012
Accepted: August 18, 2012
Published online: August 28, 2012
Abstract

AIM: To elucidate the colonoscopic features of serrated lesions of the colorectum using magnifying colonoscopy.

METHODS: Broad division of serrated lesions of the colorectum into hyperplastic polyps (HPs), traditional serrated adenomas (TSAs), and sessile serrated adenomas/polyps (SSA/Ps) has been proposed on the basis of recent molecular biological studies. However, few reports have examined the colonoscopic features of these divisions, including magnified colonoscopic findings. This study examined 118 lesions excised in our hospital as suspected serrated lesions after magnified observation between January 2008 and September 2011. Patient characteristics (sex, age), conventional colonoscopic findings (location, size, morphology, color, mucin) and magnified colonoscopic findings (pit pattern diagnosis) were interpreted by five colonoscopists with experience in over 1000 colonoscopies, and were compared with histopathological diagnoses. The pit patterns were categorized according to Kudo’s classification, but a more detailed investigation was also performed using the subclassification [type II-Open (type II-O), type II-Long (type II-L), or type IV-Serrated (type IV-S)] proposed by Kimura T and Yamano H.

RESULTS: Lesions comprised 23 HPs (23/118: 19.5%), 39 TSAs (39/118: 33.1%: with cancer in one case), 50 SSA/Ps (50/118: 42.4%: complicated with cancer in three cases), and six others (6/118: 5.1%). We excluded six others, including three regular adenomas, one hamartoma, one inflammatory polyp, and one juvenile polyp for further analysis. Conventional colonoscopy showed that SSA/Ps were characterized as larger in diameter than TSAs and HPs (SSA/P vs HP, 13.62 ± 8.62 mm vs 7.74 ± 3.24 mm, P < 0.001; SSA/Ps vs TSA, 13.62 ± 8.62 mm vs 9.89 ± 5.73 mm, P < 0.01); common in the right side of the colon [HPs, 30.4% (7/23): TSAs, 20.5% (8/39): SSA/P, 84.0% (42/50), P < 0.001]; flat-elevated lesion [HPs, 30.4% (7/23): TSAs, 5.1% (2/39): SSA/Ps, 90.0% (45/50), P < 0.001]; normal-colored or pale imucosa [HPs, 34.8% (8/23): TSAs, 10.3% (4/39): SSA/Ps, 80% (40/50), P < 0.001]; and with large amounts of mucin [HPs, 21.7% (5/23): TSAs, 17.9% (7/39): SSA/Ps, 72.0% (36/50), P < 0.001]. In magnified colonoscopic findings, 17 lesions showed either type II pit pattern alone or partial type II pit pattern as the basic architecture, with 14 HPs (14/17, 70.0%) and 3 SSA/Ps. Magnified colonoscopy showed the type II-O pit pattern as characteristic of SSA/Ps [sensitivity 83.7% (41/49), specificity 85.7% (54/63)]. Cancer was also present in three lesions, in all of which a type VI pit pattern was also present within the same lesion. There were four HPs and four TSAs each. The type IV-S pit pattern was characteristic of TSAs [sensitivity 96.7% (30/31), specificity 89.9% (72/81)]. Cancer was present in one lesion, in which a type VI pit pattern was also present within the same lesion. In our study, serrated lesions of the colorectum also possessed the features described in previous reports of conventional colonoscopic findings. The pit pattern diagnosis using magnifying colonoscopy, particularly magnified colonoscopic findings using subclassifications of surface architecture, reflected the pathological characteristics of SSA/Ps and TSAs, and will be useful for colonoscopic diagnosis.

CONCLUSION: We suggest that this system could be a good diagnostic tool for SSA/Ps using magnifying colonoscopy.

Keywords: Serrated adenoma, Sessile serrated adenoma/polyp, Hyperplastic polyps, Traditional serrated adenomas, Conventional colonoscopy, Magnifying colonoscopy, Pit patterns, Serrated lesions