Superficial Depressed Type (IIc) Early Cancer of the Colon : Report of Two Cases

Two cases of superficial depressed type (IIc) early cancer of the colon are reported. Case 1 was a 65-year-old male and case 2 a 69-year old male. The lesion was located in the descending colon in both cases, and was removed by strip biopsy endoscopically in the former and surgically in the latter. The size of the lesion after resection was 6 mm in case 1 and 5 mm in case 2. Histopathologically, both cases were well differentiated adenocarcinoma without adenomatous components, and carcinoma developed de novo by submucosal (sm) invasion. As to the immunohistochemical staining of the cancer tissue by tumor associated antigen, case 1 showed a strong expression of carcinoembrionic antigen (CEA) and partial expression of sialyl Lewisx, and case 2 showed expressions of both CEA and sialyl Lewisx . The nuclear DNA content by flow cytometry was aneuploid only in case 1. Thus, although the two cases were morphologically the same IIc type cancer, the process of carcinogenesis and secondary phenomena varied