Pathological Reporting of Serrated Lesions of the Colorectum
Pathological Reporting of Serrated Lesions of the Colorectum
Bowel cancer screening programmes have highlighted to endoscopists and clinicians the spectrum of serrated colorectal lesions. One of the most significant developments has been the recognition that sessile serrated lesions (SSLs), while bearing histological resemblance to hyperplastic polyps (HPs), may be associated with the enhanced development of epithelial dysplasia and colorectal adenocarcinoma. Different minimum criteria exist for the diagnosis of SSLs and their differentiation from HPs. Furthermore, the spectrum of terminology used to describe the entire range of serrated lesions is wide. This variability has impaired interobserver agreement during their histopathological assessment. Here, we provide guidance for the histopathological reporting of serrated lesions, including a simplified nomenclature system. Essentially, we recommend use of the following terms: HP, SSL, SSL with dysplasia, traditional serrated adenoma (TSA) and mixed polyp. It is hoped that this standardisation of nomenclature will facilitate studies of the biological significance of serrated lesions in terms of the relative risk of disease progression.
Bowel cancer screening programmes have highlighted the histopathological assessment of serrated colorectal lesions as a problematic area. The terminology used to describe lesions within this spectrum is variable and the suggested minimum diagnostic criteria for some lesions differ between authorities. This has led to poor interobserver agreement during the histopathological assessment of this range of entities. One of the most difficult areas is the nomenclature of and diagnostic criteria for sessile serrated lesions (SSLs) (also termed 'sessile serrated adenoma' (SSA) or 'SSA/polyp' (SSA/P)). This is particularly important as these lesions, while bearing histological resemblance to hyperplastic polyps (HPs), may be associated with the early development of epithelial dysplasia and colorectal adenocarcinoma. Therefore, distinction of these lesions from HPs—that are associated with little or no increase in colorectal cancer risk—is very important. However, application of different diagnostic criteria may lead to differing thresholds for a diagnosis of SSL between reporting histopathologists. The levels of risk of disease progression associated with lesions diagnosed using these differing criteria are unclear. Variations in the application of terminology may also result in the same lesion being afforded different names by reporting pathologists. This can lead to confusion among clinical teams managing these patients and may inhibit studies of the biological significance of these lesions and the risk of disease progression associated with various histopathological factors.
This review provides guidance relating to a simplified nomenclature and classification system for serrated colorectal lesions.
Abstract and Introduction
Abstract
Bowel cancer screening programmes have highlighted to endoscopists and clinicians the spectrum of serrated colorectal lesions. One of the most significant developments has been the recognition that sessile serrated lesions (SSLs), while bearing histological resemblance to hyperplastic polyps (HPs), may be associated with the enhanced development of epithelial dysplasia and colorectal adenocarcinoma. Different minimum criteria exist for the diagnosis of SSLs and their differentiation from HPs. Furthermore, the spectrum of terminology used to describe the entire range of serrated lesions is wide. This variability has impaired interobserver agreement during their histopathological assessment. Here, we provide guidance for the histopathological reporting of serrated lesions, including a simplified nomenclature system. Essentially, we recommend use of the following terms: HP, SSL, SSL with dysplasia, traditional serrated adenoma (TSA) and mixed polyp. It is hoped that this standardisation of nomenclature will facilitate studies of the biological significance of serrated lesions in terms of the relative risk of disease progression.
Introduction
Bowel cancer screening programmes have highlighted the histopathological assessment of serrated colorectal lesions as a problematic area. The terminology used to describe lesions within this spectrum is variable and the suggested minimum diagnostic criteria for some lesions differ between authorities. This has led to poor interobserver agreement during the histopathological assessment of this range of entities. One of the most difficult areas is the nomenclature of and diagnostic criteria for sessile serrated lesions (SSLs) (also termed 'sessile serrated adenoma' (SSA) or 'SSA/polyp' (SSA/P)). This is particularly important as these lesions, while bearing histological resemblance to hyperplastic polyps (HPs), may be associated with the early development of epithelial dysplasia and colorectal adenocarcinoma. Therefore, distinction of these lesions from HPs—that are associated with little or no increase in colorectal cancer risk—is very important. However, application of different diagnostic criteria may lead to differing thresholds for a diagnosis of SSL between reporting histopathologists. The levels of risk of disease progression associated with lesions diagnosed using these differing criteria are unclear. Variations in the application of terminology may also result in the same lesion being afforded different names by reporting pathologists. This can lead to confusion among clinical teams managing these patients and may inhibit studies of the biological significance of these lesions and the risk of disease progression associated with various histopathological factors.
This review provides guidance relating to a simplified nomenclature and classification system for serrated colorectal lesions.
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