KRT7 and anus neoplasm: This tumor had the same pathology as the anal tumor, well- to moderately differentiated adenocarcinoma, and the cytokeratin (CK) 7 and CK20 immunohistochemical staining patterns were also identical: CK7 was negative in both the rectal and anal the adenocarcinomas, while CK20 was positive in both tumors (Figs. 3 and 4).