Malignant polyp

Malignant polyps are now being encountered more frequently because of increased colorectal cancer screening. Endoscopy offers a minimally invasive option for treating some malignant polyps thus reducing surgical morbidity and mortality. This chapter reviews the endoscopic assessment of colorectal polypoid lesions and risk stratification using gross polyp morphology (Paris classification), lesion surface appearance (Kudo pit pattern and mucosal microvessel appearance, via high-magnification chromoendoscopy and narrow-band imaging), and by the lesion's lifting characteristics (“nonlifting sign”). In combination, these features allow an assessment of the potential for malignancy as well as the likely depth of submucosal invasion, so as to guide appropriate management. We also consider possible adjunct assessment modalities, such as endoscopic ultrasound, and discuss postpolypectomy histologic classification, including Haggitt staging for pedunculated lesions and Kikuchi staging for sessile lesions or laterally spreading tumors. Finally, we describe endoscopic resection techniques for removal of malignant polyps, including endoscopic mucosal resection and endoscopic submucosal dissection, and compare these with surgical management options.