Do serrated neoplasms of the small intestine represent a distinct entity? Pathological findings and molecular alterations in a series of 13 cases

Abstract

Aims: To characterize pathological, immunohistochemical and molecular features of small intestinal serrated neoplasms. Methods and results: We report 13 serrated neoplasms located predominantly in the duodenum (median age, 71 years; male to female ratio, 7:6). The serrated adenomas demonstrated prominent serration, ectopic crypt formations and cytological features reminiscent of colorectal traditional serrated adenomas. Almost half the serrated adenomas demonstrated high-grade dysplasia or were associated with an adenocarcinoma. Immunohistochemical and molecular analysis showed an intestinal (CDX2-positive) phenotype in all tumours, abnormal β-catenin staining in three cases (23%), abnormal ..