A 75-year-old man visited our hospital with a colonic lesion. Colonoscopy revealed a 0-Is lesion of the sigmoid colon. Although the size was 6mm, the top surface broke off and the submucosa seemed thick. Magnifying endoscopy with narrow band imaging (NBI) revealed a Type 2B lesion according to the Japan NBI Expert Team classification, and chromoendoscopy revealed VI high irregularity in the pit pattern. By endocytoscopy (EC) the lesion was classified as EC3b. We diagnosed it as an adenocarcinoma with submucosal (SM) massive invasion and performed laparoscopic sigmoidectomy. Pathological findings were the following : moderately differentiated adenocarcinoma (tub2) , pT1b (SM3000µm) , ly0, v1, pN0 (0/10) , pPM0, pDM0, budding grade 3.
This was a very small lesion with SM massive invasion that we could diagnose without endoscopic resection because of close inspection by endoscopy.
