Sessile serrated polyps show a predilection for the proximal colon and are typically large, spanning more than 5 mm in most cases. They are often difficult to detect endoscopically and may be larger than they appear because they have indistinct borders. Sessile serrated polyps lack overt dysplasia and share some morphologic features with hyperplastic polyps but display a variety of unique features. The crypts are usually dilated in the deep mucosa, show branching, or display horizontal orientation above the muscularis mucosae. Most sessile serrated polyps harbor BRAF mutations and many show DNA hypermethylation, leading some investigators to conclude that they are precursors to colorectal cancers that show similar molecular alterations. The observed association between nondysplastic serrated polyps and colon cancer has led to the concept of a serrated neoplastic pathway to explain the pathogenesis of sporadic colon cancers with microsatellite instability. Recently proposed guidelines for diagnosis, treatment, and surveillance of patients with sessile serrated polyps have substantial implications for patient care, as illustrated in the following case. A 47-year-old healthy woman underwent screening colonoscopy, at which time she was found to have a 4-cm sessile polyp in the ascending colon. Multiple biopsies yielded a diagnosis of sessile serrated polyp. Unfortunately, the lesion was not amenable to endoscopic excision, and thus, the patient underwent right colectomy. The specimen contained a sessile serrated polyp without dysplasia. In this report, we discuss the concept of a serrated neoplastic pathway, evidence for cancer risk among patients with these lesions, and recently proposed management guidelines.
From the Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY.
Reprints: Kathryn C. Piotti, MD, Department of Pathology and Laboratory Medicine, New York Presbyterian Hospital-Weill Cornell Medical Center, 525 East 68th St, New York, NY 10065. E-mail: firstname.lastname@example.org.
The authors have no funding or conflicts to declare.