# Clinical and Endoscopic Characteristics of Patients with Oligopolyposis

## TL;DR

This study examines the clinical and endoscopic features of patients with oligopolyposis, finding that only a small proportion carry genetic mutations, with no major differences in cancer rates or outcomes.

## Contribution

The study highlights ethnic differences in mutation frequency among oligopolyposis patients but finds no significant clinical differences between mutation carriers and non-carriers.

## Key findings

- Pathogenic mutations were found in 16% of genetically tested oligopolyposis patients.
- Arab ethnicity was significantly more common among mutation carriers.
- No significant differences in cancer rates or mortality were observed between carriers and non-carriers.

## Abstract

Background/Objectives: Oligopolyposis is a rare condition characterized by 10 to 100 adenomas in the colon. We aimed to investigate the clinical and endoscopic features of patients with oligopolyposis by comparing patients who carried pathogenic mutations and those who did not. Methods: This retrospective study included patients with a cumulative count of 10–100 adenomas found in the colon, at a single center. Clinical, endoscopic, and genetic data were analyzed. Results: A total of 155 patients were identified as having oligopolyposis. Genetic testing using a multigene panel was performed among 85 (55%) patients, while founder or family mutation testing was performed among 7 (4.5%) patients. No genetic testing was carried out in 63 (40.5%) patients. Pathogenic polyposis-related mutations were identified in 14 (16%) out of 85 patients who underwent genetic testing. Among these, seven (50%) mutations were found in the APC gene and seven (50%) in the MUTYH gene. A significantly higher proportion of mutation carriers were of Arab ethnicity (35.7% vs. 4.2%, p < 0.001). There was no significant difference between carriers and non-carriers with regard to family history of polyps or cancer. Colorectal cancer was found to be the initial presentation in three (21%) carriers and five (7%) non-carriers. Colonic surgeries were reported among 4 (28.6%) carriers and 13 (18.6%) non-carriers. No significant differences in the rates of colorectal cancer or death were observed between carriers and non-carriers. Conclusions: Only a small proportion of patients with oligopolyposis were found to be mutation carriers, with significant ethnic differences in mutation frequency but no notable differences in clinical features, colorectal cancer rates, or mortality.