Abstract

Assessing a locally excised colorectal adenoma for malignancy is a common but often challenging scenario. This article outlines a simple, stepwise approach to this diagnostic assessment. The first steps are to assess for high-grade dysplasia and, if present, to determine whether any neoplastic glands lie within the submucosa. If so, a distinction must then be made between epithelial misplacement and adenocarcinoma; this process is aided by certain clinical and endoscopic data together with assessment of six key histological features. If adenocarcinoma is diagnosed, a final step is to report the presence/absence of high-risk features of polyp cancers because this will then determine if further surgical resection is required for that malignancy. Caveats, uncertainties and newly introduced concepts exist at several steps of the assessment pathway presented and are therefore discussed in detail throughout the article.