1992 Volume 34 Issue 11 Pages 2605-2609_1
A 41-year-old male visited to our hospital because of lower abdominal pain. A tiny reddish lesion in the rectum was found by endoscopy and tubular adenoma with severe atypia was identified. Transanal excision was performed. On the fixed specimen, a depressed lesion measuring 4×2mm in size was revealed and well differentiated adenocarcinoma involving the submucosa without adenomatous component was recognized histologiacally. The second case was a 56-year-old male who was followed up after the operation of colonic polyp. Endoscopically, a small depressed lesion was detected in the sigmoid colon and treated by strip biopsy. The fixed specimen revealed a depressed lesion 5×4mm in size and the histological examination showed well differentiated adenocarcinoma involving the submucosa without adenomatous component. It was suggested that these cases were depressed lesions of "de novo" cancers and the submucosal involvment could occur in such small lesions of 5mm or less in size.
