How to "pick up" colorectal serrated lesions and polyps in daily histopathology practice: From terminologies to diagnostic pitfalls

Abstract

Over the last decade, our knowledge of colorectal serrated polyps and lesions has significantly improved due to numerous studies on this group of precursor lesions. Serrated lesions were misleading as benign before 2010, but they are currently reclassified as precancerous lesions that contribute to 30% of colorectal cancer through the serrated neoplasia pathway. The World Health Organization updated the classification for serrated lesions and polyps of the colon and rectum in 2019, which is more concise and applicable in daily practice. The responsible authors prescribe that “colorectal serrated lesions and polyps are characterized by a serrated (sawtooth or stellate) architecture of the epithelium.” From a clinical standpoint, sessile serrated lesion (SSL) and SSL with dysplasia (SSLD) are the two most significant entities. Despite these advancements, the precise diagnosis of SSL and SSLD based mainly on histopathology remains challenging due to various difficulties. This review describes the nomenclature and the terminology of colorectal serrated polyps and lesions and highlights the diagnostic criteria and obstacles encountered in the histopathological diagnosis of SSL and SSLD.

Keywords: Sessile serrated lesions; Sessile serrated lesions with dysplasia; Serrated polyps; Sessile serrated adenoma; Benign hyperplastic polyps; Serrated lesions/polyps

Core Tip: The “serrated neoplastic pathway”, a crucial and significant aspect of our comprehension of cancer, has seen substantial advancement over the past decade. While the literature has made significant strides in molecular biology and diagnostic criteria, there is room for improvement in achieving a consensus on terminology. This review, which could potentially revolutionize your practice, aims to offer an in-depth understanding of essential criteria, the intricacies involved in diagnosing sessile serrated lesion (SSL) and SSL with dysplasia, the two entities of utmost clinical importance, and the ongoing discussions related to terminology.