| Theme |
Management of large colorectal polyp --Indication and technique of endoscopic treatment |
| Title |
Clinicopathological characteristics of colorectal polyps larger than 20 mm |
| Author |
Yoichi Ajioka |
First Department of Pathology, Niigata University School of Medicine |
| Author |
Hidenobu Watanabe |
First Department of Pathology, Niigata University School of Medicine |
| Author |
Shunichi Hayashi |
Department of Gastroenterology, Niigata Rinko General Hospital |
| Author |
Yutaka Suzuki |
Third Department of Internal Medicine, Niigata University School of Medicine |
| [ Summary ] |
More than 95% of colorectal polyps larger than 20mm were classified either as adenomas or adenocarcinomas. Non-neoplastic, tumor-like lesions and non-epithelial neoplasia displayed incidence rates of 1% and 3 to 4%, respectively. Juvenile polyps and Peutz-Jeghers polyps representatived tumor-like lesions. For non-epithelial neoplasia, lipoma was mostly frequent, seen and were found in either the right colon or the transverse colon. Epithelial neoplasias larger than 20mm can be classified into two groups by their different growth patterns; one having a low potential for submucosal invasion (remaining mucosal lesions when they are larger than 20mm), and are frequently accompanied by adenomatous components. One of these has a highly invasive potential (so the most of these lesions were classified as invasive carcinomas, when over 20mm in size). Macroscopic classification by mucosal appearance was performed on adenomas and early carcinomas larger than 20mm. They can be classified as Lobular(L), Flat(F), Villous(V), Gylus-like(Gy), Nodular(Nod), Massive(M) or Amorphous(A). V, Gy and Nod types consisting of larger lesions (mainly over 3Omm) and showed a low incidence of submucosal invasion (0 to 24.6%). While M and A types were rather smaller (less than 40mm). However, incidences of submucosal invasion were high (79.3 to 100%). These two macroscopic groups may correspond to two groups with different growth patterns. |