Snapshot A 60-year-old healthy man undergoes a screening colonoscopy. He has been staying active, does not smoke, denies any bloody or dark stools, changes in stool, abdominal pain, or fatigue. His prior colonoscopy was normal. During today’s colonoscopy, his gastroenterologist notes a small pedunculated growth in the descending colon. Introduction Overview abnormal growth of tissue from the colonic mucosa most are benign but some can progress to cancer treatment is resection can be part of a polyposis syndrome familial adenomatous polyposis juvenile polyposis syndrome Peutz-Jeghers syndrome Gardner syndrome Genetics APC KRAS T53 BRAF microsatellite instability mismatch repair Epidemiology Incidence highly prevalent (30-50% of adults) 90% occur after 50 years of age can be hyperplastic and benign or adenomatous with malignant transformation up to 90% are hyperplastic polyps most commonly in sigmoid and rectum Risk factors smoking obesity high-fat diet red meat ETIOLOGY Pathogenesis pathophysiology hyperplastic polyp non-dysplastic proliferation of the colonic epithelium adenomatous polyp growth and malignant transformation with genetic mutations can be tubular, tubulovillous, villous, or sessile serrated villous has the greatest malignant potential Presentation Symptoms most often asymptomatic common symptoms rectal bleeding change in stool caliber Physical exam inspection endoscopically visualized provocative tests digital rectal exam occult blood palpated if distal Imaging Lower gastrointestinal radiograph series may detect larger polyps Virtual colonoscopy with computed tomography scan limited use outside of research may detect larger polyps poor sensitivity Studies Serum labs tumor markers CEA CA19-9 associated but not used for screening or diagnosis Invasive studies stool occult blood test neither sensitive nor specific endoscopic evaluation colonoscopy is the best evaluation alternatives include flexible sigmoidoscopy or pill capsule endoscopy obtain a biopsy for pathological evaluation Histology H&E of endoscopic biopsy samples is diagnostic type of polyp size degree of dysplasia Differential Inflammatory bowel disease key distinguishing factor pseudopolyp from the scarring process in response to inflammation Familial adenomatous polyposis key distinguishing factors many polyps younger age Peutz-Jeghers syndrome key distinguishing factors hamartomatous polyps mucocutaneous hyperpigmentation Treatment Surgical endoscopic polypectomy indications for all visualized polyps colectomy indications endoscopically unresectable polyps multiple large adenomas high-grade dysplasia invasive adenocarcinoma severe gastrointestinal bleeding Complications Gastrointestinal bleeding Adenocarcinoma of the colon risk factors time undetected treatment depends on stage Prognosis Natural history malignant progression of adenomatous polyps can take years Good progosis with polypectomy