Sessile serrated adenomas strongly predispose to synchronous serrated polyps in non-syndromic patients

Aims: To determine the prevalence of various colonic polyps removed during a recent 8-month period; to determine the interobserver agreement in the diagnosis of serrated polyps; and to determine if harbouring a sessile serrated adenoma (SSA) predisposes to the presence of synchronous polyps with similar histology. Methods and results: All polyps resected during an 8-month period at a single tertiary medical centre were analysed. We also analysed all polyps in patients with an SSA or SSA with dysplasia since 2003. SSAs accounted for 4.3% of colonic polyps removed during an 8-month period. A review of 276 serrated polyps by two pathologists revealed good interobserver agreement (κ = 0.66). Patients with one SSA were more likely to harbour additional serrated polyps. After removal of the index SSA, 18% of their remaining polyps were SSAs, SSAs with dysplasia, and traditional serrated adenomas, contrasting with the ∼5% prevalence of these polyps in the control population. The hyperplastic polyps in the study population were also twice as likely to occur proximal to the splenic flexure. Conclusions: These data indicate that there is a strong colonic mucosal field defect in patients with sporadic SSAs that predispose them to develop additional serrated polyps.