Polyp identification and marking: Chromoscopy, high-resolution and high-magnification endoscopy, tattooing, and clipping

The most current methods for polyp identification involve the use of surface staining. The use of staining during colonoscopy or chromoscopy differentiates indeterminate mucosal findings from adenomas, hyperplastic polyps from adenomas, and the borders of large sessile polyps during their removal. Chromoscopy is ideally performed with newer high-resolution video colonoscopes. Chromoscopy combined with high-magnification colonoscopes is currently a research tool used to identify and quantitate aberrant crypt foci, which are suspected to represent the earliest precursor of the adenoma. Polyp site marking can be best performed by tattooing with India ink or commercial, tattoo parlor-type inks. A short-term alternative to polyp site marking is the use of catheter-placed clips. These can also be used to close polypectomy site defects as a measure to avoid complications such as bleeding and perforation. The techniques described are all readily adaptable to the practice of colonoscopy today.