General considerations relating to polypectomy
In the absence of magnifying endoscopy combined with dye spraying, or in some studies, Narrow Band Imaging, it is often not possible to determine the histological type of a polyp by endoscopic inspection. Diminutive hyperplastic polyps and adenomas (5 mm or less) may be indistinguishable. The unusual large hyperplastic polyp may mimic an adenoma.
All polyps should be considered for removal. Diminutive polyps (5mm or less) may be too numerous to be cleared completely. In patients with multiple small polyps, a sample of at least three should be taken for histological study. However, if a syndromic diagnosis is under consideration, then sampling of many more polyps is important, to guide decisions on which gene should be subjected to mutational analysis.
Large sessile adenomas
In most centres, large sessile polyps are removed by piecemeal endoscopic mucosal resection (EMR) although this can make histological evaluation of completion of polypectomy difficult or impossible. EMR or Endoscopic Submucosal Dissection (ESD) (which secures the specimen in one piece) can be successfully (95%) achieved when done by well trained specialists in specialised centres with the appropriate equipment.
Tattooing polypectomy sites
With any lesion identified at colonoscopy, the colonoscopist should assess whether the lesion can be safely removed endoscopically. For larger polyps or those with features suspicious of malignancy such as an irregular or ulcerated surface, tattooing of the site should be systematically considered. If there is any possibility of a need for later surgical resection of the site, the area should be tattooed, as this aids the surgeon, the pathologist’s examination of the resected specimen and the accuracy of the histopathology report. The tattoo should be placed 2-3cm distal to the lesion (to avoid submucosal fibrosis which makes any further attempt at endoscopic polypectomy more difficult, dangerous and unlikely to be complete) rather than ‘at’ or under the polyp.
This is particularly important in centres where laparoscopic resections are done, as the surgeon has no capacity to feel the polyp or polypectomy site at laparoscopy.
In the event that malignancy is identified unexpectedly in a polyp which has not been tattooed and surgery is the preferred further management strategy, early re-endoscopy is needed to tattoo the site, preferably within a week.
Tattooing any polyp site where there is a possibility that surgical resection will be needed is important at the primary colonoscopy if at all possible, or very soon after with a second procedure. This is necessary even for conventional surgery, as the site of polypectomy may well be impalpable, but particularly important where follow-up treatment may be laparoscopic, as the surgeon has no capacity to palpate the area.
- East JE, Saunders BP, Jass JR. Sporadic and syndromic hyperplastic polyps and serrated adenomas of the colon: classification, molecular genetics, natural history, and clinical management. Gastroenterol Clin North Am 2008 Mar;37(1):25-46, v Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/18313538.
- Half E, Bercovich D, Rozen P. Familial adenomatous polyposis. Orphanet J Rare Dis 2009 Oct 12;4:22 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/19822006.
- Nivatvongs S. Complications in colonoscopic polypectomy. An experience with 1,555 polypectomies. Dis Colon Rectum 1986 Dec;29(12):825-30 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/3491746.
- Boparai KS, Mathus-Vliegen EM, Koornstra JJ, Nagengast FM, van Leerdam M, van Noesel CJ, et al. Increased colorectal cancer risk during follow-up in patients with hyperplastic polyposis syndrome: a multicentre cohort study. Gut 2010 Aug;59(8):1094-100 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/19710031.
- Fennerty MB, Sampliner RE, McGee DL, Hixson LJ, Garewal HS. Intestinal metaplasia of the stomach: identification by a selective mucosal staining technique. Gastrointest Endosc 2017 Sep 23;38(6):696-8 Abstract available at http://www.ncbi.nlm.nih.gov/pubmed/1282115.