Early Rectal Cancer With Submucosal Infiltration: When to Avoid Cold Snare Polypectomy for

Abstract

A 65-year-old man was referred to our hospital because of the presence of a rectal lesion. The patient had an 8-mm reddish sessile protruding lesion (Paris 0-Is) on the rectosigmoid with white light imaging (a). Cold snare polypectomy (CSP) is considered appropriate for adenomatous polyps measuring <10 mm. However, magnifying narrow-band imaging showed irregular vessel and surface patterns (Japan NBI Expert Team type 2B) (b). Magnifying chromoendoscopy with crystal violet staining revealed mild irregularity of the pits (Kudo type VI low grade) indicative of cancer (c). Pretreatment diagnosis indicated early rectal cancer, and the estimated depth of invasion was superficial submucosal invasion (Tis–T1a [SM1]). Therefore, endoscopic mucosal resection was performed instead of CSP. Histopathology revealed a well-differentiated tubular adenocarcinoma with an adenoma component and depth of pT1b (SM: 1,800 μm) (d). CSP was safe and effective against lesions measuring <10 mm, with the rate of en bloc resection reaching 100%. Nevertheless, a precise pretreatment diagnosis is required. After the detection of Japan NBI Expert Team type 2B, treating physicians should perform magnifying chromoendoscopy to evaluate the pit pattern. We report a rare case of a lesion measuring <10 mm in diameter with massive submucosal infiltration treated with endoscopic mucosal resection instead of CSP. (Informed consent was obtained from the patient to publish these images.)