A New Type Of Colorectal Precancerous Lesion: Study On Characteristics Of Serrated Adenomas

Background and ObjectivesThe morbidity of colorectal cancer (CRC), the fourth common carcinoma, is increasing yearly in our country. Histolgenesis of CRC includes "adenoma-canceration" pathway and "denove cancer" pathway, generally. Recently, increasing evidences have indicated the existence of the third process, namely "serrated polyp-canceration" process, which introduces that hyperplastic polyps (HP/HPs) can advance into large intestinal adenocarcinoma by the transformation of serrated adenomas (SA/SAs). The theory with practical value of clinical diagnose and treatment, which explodes the conventional view of HP without canceration, reminds endoscopists and pathologists to pay attention to the recognization and management of such specific lesions.Without clear histogenesis, SA may originate from insecondary dysplasia in HP, or two different structure independently developing and inter-impacting, or the histological allomixis of HP and adenomatous structure. Recently, studies mainly on qualitative pathology, immunohistochemistry, microsatellite instability and so on, abroad, tended to regard SA as an independent type of large intestinal epithelial tumour. SA is not thought highly in our country and many endoscopists and pathologists treate them as HPs, because of the characteristics of low morbidity and having similar endoscopic and microscopic features. Endoscopically and pathologically, 7 SAs and 2 laterally spreading tumors (LST/LSTs) combined with...