Fundic gland polyp dysplasia is common in familial adenomatous polyposis.

Background & Aims: Fundic gland polyps (FGPs) are common in familial adenomatous polyposis (FAP) but have been considered nonneoplastic. Gastric carcinoma arises from FGPs in FAP presumably from a dysplasia-carcinoma pathway. Our study examined the prevalence of FGPs and FGP dysplasia in FAP and identified endoscopic or demographic features associated with FGPs and dysplasia.

Methods: Demographic and endoscopic information were obtained prospectively from 75 consecutive subjects undergoing upper-endoscopic surveillance for FAP. Systematic biopsy specimens of FGPs, normal-appearing fundic mucosa, and antral mucosa for Helicobacter pylori were obtained. Multivariable analysis assessed the association of demographic or endoscopic factors with the presence of FGP or FGP dysplasia.

Results: FGPs were detected in 88% of subjects and were dysplastic in 41% (38% low grade, 3% high grade). H pylori infection was rare in subjects with vs without FGPs (1.5% vs 33.3%, P = .005). In the multivariable analysis larger FGP size (odds ratio [OR], 4.0; 95% confidence interval [CI], 1.1-14.4), higher stage of duodenal polyposis (OR, 2.3; 95% CI, 1.2-4.5), and antral gastritis (OR, 11.2; 95% CI, 1.2-103.9) were associated with FGP dysplasia. Exposure to acid-suppressive medications was associated with a marked decrease in dysplastic FGPs (OR, 0.14; 95% CI, 0.03-0.64).

Conclusions: The majority of FAP patients have FGPs and nearly half will have dysplastic FGPs. There is an inverse relationship between H pylori and FGPs. FGP dysplasia is associated with larger polyp size, increased severity of duodenal polyposis, and antral gastritis. Acid-suppressive therapy use appears protective against dysplasia in FGPs.