Interventional Chromoendoscopy for Colorectal Lesion Resection

TECHNIQUE ARTICLE

Klaus Mönkemüller, MD, PhD, FASGE, FESGE, FJGES

Professor of Medicine, Department of Gastroenterology, Carilion Memorial Hospital, Virginia Tech Carilion School of Medicine, Roanoke, USA

Correspondence: Klaus Mönkemüller, MD, PhD — Department of Gastroenterology, Carilion Memorial Hospital, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA

Abstract

Background: Interventional chromoendoscopy combines submucosal injection with chromoendoscopy dye to enhance lesion visualization and create a safety cushion during endoscopic mucosal resection (EMR). This technique provides real-time depth assessment through color differentiation between mucosal, submucosal, and muscularis propria layers.

Case: A 54-year-old woman undergoing surveillance colonoscopy was found to have a flat colorectal lesion classified as a laterally spreading tumor (Paris 2a, ~15 mm, Kudo pattern IIIS). The lesion was injected with Everlift, a submucosal lifting agent containing a pre-mixed colored substance, creating a blue submucosal cushion that clearly delineated the neoplastic tissue (appearing white) from the deeper layers. EMR was performed with complete resection, and prophylactic clips were placed to close the defect.

Conclusion: Interventional chromoendoscopy enhances the safety and completeness of EMR by providing a color-coded interface that aids in lesion characterization, depth assessment during resection, and early identification of complications requiring prophylactic closure.

Keywords: interventional chromoendoscopy; endoscopic mucosal resection; EMR; laterally spreading tumor; Everlift; submucosal injection; Kudo pit pattern; Paris classification; colorectal polyp; prophylactic clip closure

★ Key Clinical Takeaways

Interventional chromoendoscopy uses a colored submucosal lifting agent (e.g., Everlift) that creates a blue submucosal cushion, making the neoplastic tissue appear white against the blue base — enhancing lesion boundaries and facilitating complete resection.
The color interface provides real-time depth assessment during EMR: blue = submucosa (safe plane), white = muscularis propria (too deep). Loss of blue color during resection signals excessive depth and should prompt immediate prophylactic clip closure.
Laterally spreading tumors classified as Paris 2a with Kudo pattern IIIS are amenable to endoscopic mucosal resection; interventional chromoendoscopy enhances visualization of these flat lesions that may be subtle under standard white light.
Prophylactic clip closure of the post-resection defect is essential when the muscularis propria is visible, to prevent immediate or delayed perforation.
The submucosal cushion created by the lifting agent serves a dual purpose: it facilitates safer snare resection by separating the lesion from the muscularis propria, and it provides chromatic depth feedback throughout the procedure.

Clinical History

A 54-year-old woman underwent surveillance colonoscopy for colorectal cancer screening.

Endoscopic Findings

A flat lesion was identified in the colon (Panel A, yellow arrow). Close-up examination revealed a small, laterally spreading tumor measuring approximately 15 mm, classified as Paris 2a, with a Kudo pit pattern IIIS (Panel B, yellow circle).

Endoscopic Technique

The lesion was injected with Everlift, a submucosal lifting agent that includes a pre-mixed colored substance (Panel C). This created a visible interface, with the neoplastic flat lesion appearing white against the blue submucosal layer (Panels C and D). The presence of the blue color allowed for clear differentiation of the superficial lesion from deeper layers, such as the submucosa and muscularis propria (Panel C, yellow stars).

After resection, a white color corresponding to the muscularis propria was observed, indicating the depth of resection (Panel E, blue arrow). The submucosa retained a bluish color. Prophylactic clips were applied to close the post-resection defect (Panel F).

Figure 1. Interventional chromoendoscopy for colorectal lesion resection. (A) Initial view of a flat colonic lesion (yellow arrow). (B) Close-up revealing a laterally spreading tumor, Paris 2a, Kudo IIIS (yellow circle). (C) After submucosal injection with Everlift showing the blue submucosal cushion with neoplastic tissue appearing white and deeper layers differentiated (yellow stars). (D) Lesion clearly delineated against the blue submucosal base. (E) Post-resection defect showing white muscularis propria (blue arrow) and blue submucosa, indicating resection depth. (F) Prophylactic clip closure of the resection defect.

Discussion

Interventional chromoendoscopy offers several advantages during endoscopic resection (EMR or ESD). First, it provides a color interface that delineates lesions that may be challenging to visualize under white light endoscopy, ensuring complete lesion characterization. Second, the submucosal cushion created by the lifting agent provides a safety base for resection, minimizing the risk of perforation.

Third, it allows for clear visualization of the third space, including submucosal layers, providing a visual element to prevent complications. If the resection is carried out too deeply, the absence of blue color in the submucosa signals excessive depth, prompting prophylactic closure with clips to prevent immediate or delayed colon perforation.

References

Parra-Blanco A, Gimeno-García AZ, Quintero E. Chromoendoscopy and new endoscopic imaging techniques. World J Gastroenterol. 2011;17(41):4541–52.
Kudo S, Hirota S, Nakajima T, et al. Colorectal tumors and pit pattern analysis. J Clin Gastroenterol. 1994;18(3):218–22.
Tanaka S, Kashida H, Saito Y, et al. JGES guidelines for colorectal endoscopic submucosal dissection/endoscopic mucosal resection. Dig Endosc. 2020;32(1):154–180.
Mönkemüller K, Wilcox CM. Interventional chromoendoscopy. Gastrointest Endosc. 2013;78:346–350.

About the author

Klaus Mönkemüller, MD, PhD, FASGE, FJGES, FESGE

Editor-in-Chief, The Practicing Endoscopist

Professor of Medicine, Carilion Memorial Hospital / Virginia Tech Carilion School of Medicine, Roanoke, Virginia, USA

Klaus Mönkemüller, MD, PhD, FASGE, FJGES, FESGE, is the editor-in-chief of The Practicing Endoscopist and the founder of EndoCollab. He is Professor of Medicine at Virginia Tech Carilion School of Medicine and a practicing endoscopist at Carilion Memorial Hospital in Roanoke, Virginia.

Dr. Mönkemüller has published extensively on endoscopic techniques and devices, with a particular focus on therapeutic endoscopy, foreign body removal, GI bleeding, and the use of caps and accessories in everyday practice. He lectures internationally and has contributed to multiple GI endoscopy textbooks and atlases.

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