Circumferential Zig‐Zag Pattern Suggesting a Superficial Origin of Colorectal Cancer

The early stage of colorectal cancer is divided into two morphological types polypoid and superficial. What percentage of advanced cancer is derived from the polypoid or superficial type is a matter of concern. The ratio of superficial variety among of ulcerated cancers was studied using those 2 cm or less in diameter, which often retain mucosal cancer. The existence of horizontal growing mucosal cancer at the marginal area of ulcerated cancer is a hallmark showing the lesion being of superficial origin. Eight (57 %) out of the 14 cases of ulcerated cancer, 2 cm or less, had this finding. This suggests that more than half of smaller colorectal cancers are of superficial origin. A zig-zag pattern (ZZP) was evident in 3 cases of superficial origin. No cases in the nonsuperficial group had the ZZP. The existence of circumferential ZZP during colonoscopic observation indicates that the cancer is of superficial origin.