A case of 11mm-sized flat elevated type colon carcinoma invading muscularis propria

Abstract

A 64-year-old man visited us to undergo further detailed examination for the sigmoid colon tumor which had been revealed by endoscopic examination in Otashiro Clinic. Colonoscopic examination revealed a 11mm-sized flat elevated lesion which was well demarcated and the type VI pit pattern was observed by magnifying endoscopic examination. This lesion was also observed positive non-lifting sign and the histopathological diagnosis of the biopsied specimen was well differentiated adenocarcinoma. Double contrast barium enema showed semilunar deformity in the lateral view of the lesion. Our diagnosis was sigmoid colon cancer invading deep submucosal layer or muscularis propria. Laparoscopic assisted sigmoidectomy was carried out. Macroscopic examination revealed a well demarcated flat elevated lesion which size was 11×8×2mm. Stereomicroscopic examination of the lesion revealed type VI pit pattern. Histopathological diagnosis was well differentiated adenocarcioma, mp3, ly1, v0, n0. According to the previous reports, a small advanced colorectal cancer of flat elevated type (IIa-like) is considered to be rare and that with type VI pit pattern is considered to be very rare.