Among the challenges encountered during endoscopic submucosal dissection (ESD), firm “retraction” of the muscularis propria towards the tumor (the “muscle-retracting” sign) can lead to non-curative resection, failure to complete ESD, or perforation [1]. Peranal endoscopic myectomy has been introduced as a means for dealing with such lesions, its merit however is currently limited to the lower rectum, where the muscularis propria is thicker compared with the rest of the colon [2]. Based on the above, we decided to illustrate a technical variation of ESD that was used to achieve an R0 resection for a cecal type 0-Is tumor with the muscle-retracting sign ([Fig. 1]; [Video 1]).
Fig. 1 Endoscopic view showing a protruded-type tumor in the cecum.
Video 1 Endoscopic submucosal dissection of a cecal protruded-type tumor with the muscle-retracting sign.
During colonoscopy, an 18-mm 0-Is tumor was identified in the cecum of an 80-year-old man with a history of post-stroke paralysis. Because of the patientʼs age and underlying disease, ESD was performed. During ESD, a muscle-retracting area was recognized in the center of the lesion and the surrounding submucosa was dissected to expose this area. The mucosal incision was then completed, leaving only the muscle-retracting area temporarily intact ([Fig. 2 a]). In order to achieve R0 resection and prevent perforation, a reopenable hemoclip was anchored onto the muscle-retracting area as close as possible to the muscularis propria ([Fig. 2 b]). The remaining tissue above the clip was then dissected, while avoiding contact between the ESD knife and the metal “arms” of the hemoclip ([Fig. 2 c]). ESD was completed without perforation, and the ESD defect was completely closed with hemoclips to prevent delayed perforation.
Fig. 2 Endoscopic images during the endoscopic submucosal dissection procedure showing: a exposure of the muscle-retracting area; b clipping of the muscle-retracting area with a reopenable hemoclip; c dissection above the hemoclip.
The muscle-retracting area could be identified on the resected surface of the specimen ([Fig. 3]). Histopathologic examination revealed tumor invasion into the submucosa (4500 μm) just above the muscularis propria (pT1b), but the resection margins were negative and no lymphovascular invasion was documented ([Fig. 4]).
Fig. 3 Macroscopic appearance of the resected specimen showing: a the mucosal surface; b the resected surface.
Fig. 4 Histopathological appearance of a section of the deepest region: a with hematoxylin and eosin (H&E) staining; b with desmin staining; c at higher magnification, showing deep submucosal invasion just above the muscularis propria, which was consistent with a type 0-Is, 15 × 15-mm adenocarcinoma (tub1, pT1b [4500 μm], ly0, v0, BD1, pHM0, pVM0).
In conclusion, upon identification of the muscle-retracting sign during ESD, clipping at the base of the muscle-retracting area and dissection above the clip can prevent perforation while maximizing resection depth to ensure an R0 resection.
Endoscopy_UCTN_Code_TTT_1AQ_2AD
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