Figure 1.
Immunohistochemical staining. A: Immunohistochemical staining of the surgical specimen demonstrating pancreato-biliary phenotype: cytokeratin-7/cytokeratin-17/mucin-1 (CK7/CK17/MUC1) positive and cytokeratin-20/homeobox protein CDX2/mucin-2 (CK20/CDX2/MUC2) negative; B: Immunohistochemical staining of the anal fissure biopsy demonstrating pancreato-biliary phenotype similar to the ampullary adenocarcinoma.