Endoscopic mesorectal dissection for precise pathologic staging and potential treatment of locally advanced rectal...

Traditional surgical techniques for rectal cancer resection may face limitations in accessing lesions at extreme rectal locations. Endoscopic mesorectal dissection (EMD) enables wide-margin resection without the constraints of conventional surgery. We present a case demonstrating the feasibility of EMD for accurate, organ-sparing staging of rectal cancer. A 67-year-old man with abdominal pain and positive Cologuard test (Exact Sciences Corporation, Madison, Wis, USA) results underwent colonoscopy that revealed a 2-cm sessile polyp 12 cm from the anal verge, removed with a hot snare. Pathology showed invasive adenocarcinoma with positive deep margins. Given challenges with low anterior resection and transanal total mesorectal excision, EMD was selected for precise staging.

Endoscopy revealed a 15-mm postpolypectomy scar with nodularity. Lesion borders were marked, and methylene blue injection achieved partial lift. A circumferential incision exposed the muscularis propria, allowing full-thickness myotomy into the perirectal fat. The 35-mm lesion was dissected and retrieved en bloc, and the defect was closed with OverStitch sutures (Boston Scientific Corporation, Marlborough, Mass, USA).

Pathology confirmed pT2 adenocarcinoma with R0 margins. The patient had no adverse events, demonstrating the technical success of EMD in achieving en bloc R0 resection.

EMD achieved en bloc R0 resection, highlighting its efficacy as a minimally invasive, organ-sparing approach for precise staging of rectal cancer.