Clarity and caution in the natural history of low-grade dysplasia in ulcerative colitis.

A substantial body of evidence supports the safety of conservative endoscopic polypectomy for discrete, adenomatous-appearing colonic polyps in patients with ulcerative colitis (UC). Much less is known about the clinicopathologic factors of low-grade dysplastic lesions at risk for subsequent high-grade dysplasia or colorectal cancer. In this issue of the American Journal of Gastroenterology, Choi et al. examine the outcome of patients with low-grade dysplasia participating in a surveillance cohort at St Mark's Hospital, one of the oldest and largest programs of its kind. Long-term follow-up of many, well-phenotyped, low-grade dysplasia cases sheds new light, and raises new questions, on our UC surveillance practice.