Much of the flat or biopsy-only detected dysplasia in inflammatory bowel disease (IBD) that had historically warranted a colectomy can now be shown to be circumscribed lesions with dye-spray or advanced endoscopic imaging. These lesions are therefore amenable to endoscopic excision with close endoscopic follow-up, though are technically very challenging. This review discusses preresection assessment of nonpolypoid or flat (Paris 0-II) lesions in colitis; lifting with colloids or hyaluronate; endoscopic mucosal resection (EMR) with spiral or flat ribbon snares; or simplified, hybrid, and full endoscopic submucosal dissection (ESD); as well as mucosal ablation. Close follow-up postresection is mandatory.