Intraductal papillary neoplasm of the biliary tract with typical clinicopathological, endoscopic features: A case report

Figure 4 Histopathologic features of the surgical specimen. A-C: Haematoxylin and eosin staining of the papillary tumour: Macrography (A); × 40 (B); × 400 (C); D-K: Immunohistochemical findings of the papillary tumour: MUC1 positivity (× 40; D); MUC2 positivity (× 40; E); MUC5AC positivity (× 40; F); MUC6 positivity (× 40; G); CK7 positivity (× 40; H); CK19 positivity (× 40; I); CK20 negativity (× 40; J); P53 wild-type (× 40; K); L: Ki-67 expression in approximately 20% of the cells, indicating moderate proliferative activity (× 40).