h&e stain. micrograph of a villous adenoma. these polyps are considered to have a high risk of malignant transformation. h&e stain. paris classification of colorectal neoplasms nice classification in colonoscopy, colorectal polyps can be classified by nice (narrow-band imaging international colorectal endoscopic): type 1type 2type 3 color same or lighter than backgroundbrowner than backgroundbrowner or darkly browner than background, sometimes patchy whiter areas vessels none, or isolated lacy vessels coursing across the lesionbrown vessels surrounding white structuresarea of disrupted or missing vessels surface pattern homogenous, or dark or white spots of uniform sizeoval, tubular or branched white structures surrounded by brown vesselsamorphous or absent surface pattern most likely pathology hyperplasiaadenomadeep submucosal invasive cancer treatment follow upmucosal or submucosal polypectomysurgical operation treatment polyps can be removed during a colonoscopy or sigmoidoscopy using a wire loop that cuts the stalk of the polyp and cauterises it to prevent bleeding. many "defiant" polyps—large, flat, and otherwise laterally spreading adenomas—may be removed endoscopically by a technique called endoscopic mucosal resection (emr), which involves injection of fluid underneath the lesion to lift it and thus facilitate endoscopic resection. saline water may be used to generate lift, though some injectable solutions such as sic 8000 may be more effective. minimally invasive surgery is indicated for polyps that are too large or in unfavorable locations, such as the appendix, that cannot be removed endoscopically. these techniques may be employed as an alternative to the more invasive colectomy. follow-up by united states guidelines, the following follow-up is recommended: baseline colonoscopy findingrecommended time until next colonoscopy normal10 years 1–2 tubular adenomas <10 mm7–10 years 3–4 tubular adenomas <10 mm3–5 years 5–10 tubular adenomas <10 mm and/or adenoma 10 mm and/or adenoma with tubulovillous or villous histology and/or adenoma with high-grade dysplasia 3 years >10 adenomas on single examination1 years piecemeal resection of adenoma 20 mm6 months