Wide Field Endoscopic Resection for Advanced Colonic Mucosal Neoplasia: Current Status and Future Directions  Bronte A. Holt, Michael J. Bourke  Clinical Gastroenterology and Hepatology  Volume 10, Issue 9, Pages 969-979 (September 2012) DOI: 10.1016/j.cgh.2012.05.020 Copyright © 2012 AGA Institute Terms and Conditions

Figure 1 Schematic representation of the Paris classification for mucosal neoplasia. Lesion morphology assists with evaluating the risk of invasive disease and guides the approach to endoscopic resection. AMN are broadly divided into protruded, flat elevated, and flat morphologies. Protruded lesions rise >2.5 mm above the surrounding mucosa and include pedunculated (0-Ip), subpedunculated (0-Isp), and sessile (0-Is) types. Flat elevated lesions (0–IIa) rise <2.5 mm above the surrounding mucosa, and features such as central depression (0–IIa + c) or a broad based nodule (0–IIa + Is) are described. Flat lesions include 0–IIb (barely perceptible elevation), 0–IIc (depressed), and 0–III (excavated) types. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 2 Examples of AMN treated by EMR. (A) A 40-mm Paris 0–IIa + Is G lesion located on the posteromedial wall of the ascending colon. (B) EMR was performed in both anterograde position and retroflexion. (C) The EMR defect is clean with characteristic blue “mat” SM staining and a number of visible vessels. (D) A near circumferential 100-mm homogenous Paris 0–IIa G lesion in the transverse colon. Histology showed tubulovillous adenoma with low-grade dysplasia. (E) The injection expands the SM layer and facilitates a large and safe resection. (F) The final vast defect with numerous visible and herniated vessels. The transverse colon is at low risk for post-EMR bleeding, and despite the resection size and number of vessels, no postprocedural bleeding occurred. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 3 After gross assessment of lesion morphology, areas of concern are focally interrogated with high-definition white light endoscopy and NBI. (A and B) 25-mm Paris 0–IIa + c NG rectal lesion with Kudo PP Vn and Sano capillary pattern IIIb. This was resected en bloc, and there was deep SMI on histology with a clear deep margin. The patient elected for careful endoscopic and radiologic surveillance. (C and D) 20-mm Paris 0–IIa + c NG lesion at the splenic flexure with Kudo PP Vi and Sano capillary pattern IIIa/b. The patient had surgical resection, and histology showed a submucosally invasive cancer arising from a tubular adenoma (T1N0M0). (E and F) 30-mm Paris 0–Is + c NG lesion in the distal sigmoid colon with a clear transition seen from Kudo PP IV to Vi. En bloc excision was performed, and histology showed a tubular adenoma with intramucosal cancer. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 4 A variety of snares are used for EMR. From left to right: serrated snare and standard oval snares, and thin wire minihex, mini-oval, and micro mini snares. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 5 Interpretation of the post-EMR defect. (A) Nonstaining SM is seen adjacent to a relatively homogenous defect with a blue “mat” appearance. (B) SM chromoendoscopy: dye solution is irrigated over the surface of the nonstaining SM. The connective tissue is avid for the dye, and staining confirms the resection has taken place in the correct mucosal plane. (C) Post-EMR defect with uninjured MP visible, characterized by concentric transversely oriented parallel muscle fibers (as opposed to the “mat” appearance of stained SM). (D) A subtle injury to the MP is demonstrated, as evidenced by a white cautery ring within the defect (“mirror target sign”). (E) When all surrounding adenoma is removed, the defect is closed with endoscopic clips applied perpendicular to the long axis of the MP defect. (F) Despite the subtle injury, this is a full thickness perforation, which was confirmed histologically. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 6 Special endoscopic resection situations. (A) A leash of thick-walled visible vessels are seen in the distal rectum after EMR. These are located in the deep SM and rarely cause significant bleeding in this location. (B) A Paris 0–IIa NG periappendiceal lesion is brought into the cecal lumen by a small volume SM injection and suction. The margin is clearly defined and hemicircumferential and is amenable to EMR. (C) The lesion is resected piecemeal using a thin-wire small snare, and SM fibrosis within and around the appendix is noted (white arrow). (D) Paris 0–IIa lesion circumferentially involving the ileocecal valve. (E) The transition point between adenomatous tissue (solid white arrow) and normal ileum (broken white arrow) can be difficult to discern. (F) Circumferential EMR around the ileocaecal valve, with no visible residual adenoma. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 7 SL of the proximal ascending colon. (A) Detection of the 35-mm 0–IIb SL was facilitated by overlying mucous and adherent stool. (B) After cleaning, the lesion and its margins are barely perceptible. (C) The SM injection defines the margins for resection. (D) Two-piece excision is performed with a serrated snare. (E) Resection of a small mucosal island within the defect using a small thin-wire mini-hex snare. (F) Bland final resection defect without residual adenoma. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 8 Postprocedural pain management algorithm. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions

Figure 9 (A and B) 15-mm Paris 0–IIa + c NG lesion with Kudo PP Vn. (C) En bloc excision performed. (D) The specimen is pinned, and endoscopic ex vivo assessment of the PP is performed. Histology showed a tubular adenoma with superficial SMI with deep and lateral margins clear. Clinical Gastroenterology and Hepatology 2012 10, 969-979DOI: (10.1016/j.cgh.2012.05.020) Copyright © 2012 AGA Institute Terms and Conditions