Hyperplastic Polyps Identified During Screening Endoscopy: Revisited by Histologic Examinations and Genetic Alterations
Date Issued
2011
Date
2011
Author(s)
Lin, Yang-Chao
Abstract
Backgrounds and Aim: Screening colonoscopy is one of the most effective methods to detect and prevent colorectal cancer by removing neoplastic polyps. Hyperplastic polyps are traditionally considered nonneoplastic and innocent ones. However, the recent discovery of serrated polyps with neoplastic potential has reclassified these polyps into hyperplastic polyps, sessile serrated adenoma and traditional serrated adenoma according to macroscopic morphology and microscopic histology. BRAF or K-RAS mutations play crucial role in these so-called serrated adenoma pathways. We aimed to revisit hyperplastic polyps identified during screening endoscopy by histologic reevaluation and genetic alterations.
Methods: A total of 253 hyperplastic polyps found by screening endoscopy were rechecked by two pathologists, and mutual agreement on diagnosis of polyps was subjected for further statistical analysis. Direct sequencing for gene mutation at BRAF V600E and KRAS G12D was performed.
Results: Among 253 hyperplastic polyps, 175 were reclassified as serrated polyps. Concordance among pathologists in diagnosing these serrated polyps was substantial (kappa=0.6672). 11.5% of the hyperplastic polyps turned out to be with neoplastic potential, including 7 sessile, 5 traditional serrated adenomas, as well as 17 conventional adenomas. Subgroup analyses revealed polyps larger than 10mm were more likely to locate in proximal colon (p=0.0004) and tended to harbor neoplastic components. Two sessile serrated adenomas and one traditional sessile adenoma had BRAF mutation, while one traditional serrated adenoma had KRAS mutation. The mean size of these mutated adenomas (9.0mm) was larger than those with wild-type genes (4.9mm).
Conclusions: Serrated polyps with neoplastic potential were prone to be overlooked as hyperplastic and innocent ones in screening colonoscopy. Both endoscopists and pathologists should pay attention to recognize the importance of serrated adenoma, especially for those polyps larger than 10mm, or locate in the proximal colon.
Subjects
Hyperplastic polyps
serrated adenomas
screening colonoscopy
colorectal cancer
SDGs
Type
thesis
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