Fig. 1. Endoscopic appearance of a subepithelial rectal lesion. (A, B) Conventional white-light endoscopy reveals a small, smooth-surfaced elevated lesion located 2 cm above the anal verge. The overlying mucosa appears intact without erythema, erosion, or ulceration. (C) Narrow-band imaging with near focus shows a regular surface pattern and capillary network, with no evidence of pit pattern irregularity or microvascular distortion.

Fig. 2. Endoscopic ultrasonographic (EUS) findings of the rectal lesion. (A) EUS using a mini-probe shows a well-demarcated, homogeneous hypoechoic lesion confined to the second and third layers of the rectal wall. (B) The lesion measures approximately 0.8 cm in maximal diameter on EUS.

Fig. 3. Endoscopic mucosal resection (EMR-L) procedure and resected specimen. (A) The lesion is captured and lifted using a band ligation device (EMR-L) following submucosal injection. (B) Post-resection ulcer base following en bloc removal of the lesion. The resection site shows a clean mucosal defect with coagulated margins and no immediate signs of perforation or bleeding. (C) Gross view of the resected specimen.

Fig. 4. Histopathologic findings of the resected rectal lesion. (A) Low-power view of the endoscopic mucosal resection specimen shows a moderately differentiated adenocarcinoma infiltrating the submucosal layer. The vertical resection margin is clear (hematoxylin and eosin [H&E] stain, ×40). (B) High-power view (H&E stain, ×100) highlights irregular glandular structures composed of atypical epithelial cells, consistent with moderately differentiated adenocarcinoma.