Endoscopic and pathological characteristics of large colorectal polyps in patients with hereditary cancer syndromes

Objective: To describe the endoscopic and histopathological characteristics of large colorectal polyps in patients with hereditary cancer risk factors. Subjects and method: A cross-sectional descriptive study with a control group was conducted using convenience sampling on 127 patients diagnosed with large colorectal polyps from January 2020 to January 2024. Result: The mean age of the hereditary group was lower than that of the non-hereditary group (52.3 ± 10.1 vs. 60.8 ± 12.5 years). The gene mutation rate in the hereditary group was 52.9%, significantly higher than in the non-hereditary group (3.2%). Polyps in the hereditary group were more frequently located in the right colon (55.6%) and had a flat morphology (31.1%). The mean polyp size was larger in the hereditary group (16.8 ± 4.2mm vs. 13.5 ± 3.6mm). The rate of adenoma, especially tubulovillous/villous type, was higher in the hereditary group (77.8% and 48.9%, respectively). High-grade dysplasia was more common in the hereditary group (40.0% vs. 15.0%). There was no significant difference in the rates of carcinoma in situ and submucosal invasive carcinoma between the two groups. Patients with FAP had a higher number of polyps, and higher rates of villous morphology and high-grade dysplasia compared to those with Lynch syndrome. Conclusion: The adenoma rate in hereditary colorectal polyps was 77.8%, with the tubulovillous/villous type accounting for 48.9%. High-grade dysplasia was significantly more frequent in the hereditary group than in the non-hereditary group (40.0% vs. 15.0%, p<0.05).