The “valley sign” in small and diminutive adenomas: prevalence, interobserver agreement, and validation as an adenoma marker

Background and Aims Classification schemes for differentiation of conventional colorectal adenomas from serrated lesions rely on patterns of blood vessels and pits. Morphologic features have not been validated as predictors of histology. The aim of this study was to describe the prevalence of the “valley sign” and validate it as a marker of conventional adenomas. Methods Three experts judged the prevalence of the valley sign in 301 consecutive small adenomas. Medical students were taught to recognize the valley and were tested on their recognition of the valley sign. Consecutive diminutive polyps were video-recorded and used to validate the association of the valley sign with conventional adenomas. Results The prevalence of the valley sign in 301 consecutive adenomas