Immunohistochemical staining of the tumor was positive for CK7 (Fig. 4c), CDX2 (Fig. 4e), and CEA expression and negative for CK20 (Fig. 4d), p16, estrogen receptor, progesterone receptor, vimentin, calretinin, and cluster of differentiation-10 expression. Here, CEACAM5 is linked to neoplasm.