大腸癌の発育進展と肉眼形態―深達度診断の視点から

Growth Patterns and Macroscopic Features of Colorectal Cancer

要旨　外科的に切除された大腸癌1,592病変から大腸癌全般についての概説的事項を検討し，そのうち最大径3cm未満の大腸癌144病変の肉眼所見と組織学的所見を，深達度診断の視点から検討した．検討例には従来の肉眼的分類が困難な例があり，また肉眼型が深達度を反映しないことがあったが，隆起の性状，陥凹の深さ，周囲粘膜の所見を検討すれば，深達度診断はある程度可能であった．隆起は表面が無構造なものほどより深部に浸潤し，陥凹は深部浸潤の存在を示し，特に絶対的陥凹はpm癌から出現し，また浸潤の程度により周囲粘膜の盛り上がりや固定されたひだの出現をみた．

　We evaluated the size, histological type, location, and shape of the surgically removed 1,592 colorectal cancers in regards to invasivity. Poorly differentiated carcinomas (por. muc. sig.) were relatively rare, but had marked invasiveness. The early cancer in the lower rectum was larger (about 3 cm) than that in any other part of the colon (2 cm). Nearly round-shaped lesions showed a tendency to have more invasive growth pattern.

　The macroscopic and microscopic findings of 144 1esions less than 3 cm in size were analyzed. We found that the macroscopic classification of colorectal cancer was not useful to estimate invasivity. We focused on the following three elements of the macroscopic findings; texture and shape of the elevation, depth of the depression, and feature of the neighboring mucosa. An elevation without superficial fine texture suggested deep invasion. A depression indicated the existence of submucosal invasion, and a deep (absolute) depression was seen when invasion reached the proper muscle layer. An elevation of the neighboring mucosa and fixed folds might appear depending on the extent of invasion. The three elements of the macroscopic findings, which described as above, seem to be useful for evaluating the extent of invasion.