Muscle Retracting Sign in Colorectal Macronodular Lesions: Prevalence, Endoscopic Submucosal Dissection Outcomes, and Submucosal Cancer Predictors.

Endoscopic submucosal dissection (ESD) is the preferred treatment for large colorectal lesions and those at risk of submucosal invasive cancer (SMIC).1 Macronodules ≥1 cm-typically seen in protruding lesions or granular mixed laterally spreading tumors (LST-GM)-are strongly associated with SMIC.2,3 The muscle retracting sign (MRS), first described by Toyonaga et al in 2015,4 appears as a triangular traction of the muscularis propria into the submucosal space. It is linked to fibrosis, a central feeding vessel, or deep invasion, but data distinguishing fibrosis-related MRS from cancer-related MRS are scarce.5.