FIGURE 4

a, Exposed protruding form of ampullary carcinoma. The papillary tumor proliferates in the common channel, on the surface of duodenal papilla, and within the intraduodenal common bile duct (hematoxylin and eosin staining, 3 ). b, Distribution of carcinomatous and adenomatous areas: the adenomatous areas are mostly present within the rim of the tumor and in the deep portion of the common channel and the common bile duct. c, Carcinomatous areas: tumor cells having bizarre nuclei and prominent nucleoli exhibit irregular tubules (hematoxylin and eosin staining, 160 ). d, Adenomatous areas: the epithelium proliferates in a tubular or villous fashion, and epithelial cells have moderate to severe nuclear atypia (hematoxylin and eosin staining, 120 ). e, p53 immunohistochemical stain in carcinomatous areas: in this case, carcinoma cells exhibit diffusely positive reaction in their nuclei (2+; 120 ). f, p53 immunohistochemical stain in adenomatous areas: tumor cells are diffusely positive (2+; 160 ). g, 60.5% of the tumor cells are positive for Ki-67 (120 ).