Intraductal papillary neoplasm of the bile duct accompanying biliary mixed adenoneuroendocrine carcinoma

Figure 3 Immunohistochemistry for cytokeratin 19, synaptophysin, and Ki-67. A: Both the solid (asterisk) and papillary (arrows) components were positive for CK19. Magnification: × 200; B: Synaptophysin expression was evident in the solid component (left), indicating a neuroendocrine tumor, but not in the papillary component (right). Magnification: × 100; C: Although Ki-67-positive cells were scarce in the papillary component (arrows), many Ki-67-positive cells were identified in the solid component (asterisk). Magnification: × 200.