Classification and endoscopic diagnosis of colorectal polyps

Background: Colorectal cancer is a common malignancy and a major health concern in Korea. The increased use of screening colonoscopies has led to improved survival of patients with colorectal cancer despite its high prevalence; this highlights the importance of early detection and removal of neoplastic polyps such as adenoma and sessile serrated lesions. Therefore, optical diagnosis of colorectal polyps is crucial in deciding whether the lesion requires removal and if endoscopic procedures can be used for its removal.Current Concepts: Several image-enhanced endoscopy (IEE) techniques and classifications can be used to improve the optical diagnosis of different polyps that match the histopathologic findings. Kudo's pit pattern classification is based on features of pit patterns observed from different types of polyps via chromoendoscopy. The Narrow-Band Imaging (NBI) International Colorectal Endoscopic (NICE) classification is an international classification based on patterns observed from NBI findings. The Japan NBI Expert Team (JNET) classification identifies different patterns observed from magnified images with NBI. The Workgroup serrAted polypS and Polyposis (WASP) classification helps to differentiate hyperplastic polyps from sessile serrated lesions. Endoscopy manufacturers have also developed IEE techniques such as I-scan, flexible spectral imaging color enhancement, and blue laser imaging/linked color imaging to highlight, delineate, and differentiate various polyps.Discussion and Conclusion: Optical diagnosis of colorectal polyps using IEE such as NBI with different classifications such as NICE, JNET, and WASP is important for differentiating neoplastic polyps and removing them with an appropriate method.