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

Figure 1 Computed tomography of the bile duct. Computed tomography revealed dilatation of the bile duct and an elevated lesion (arrow) at the bottom of the lower bile duct.

Figure 2 Pathological findings from the resected bile duct (hematoxylin eosin staining). A: A semi macro cross-sectional image of the resected extrahepatic bile duct. In the dilated bile duct, the tumor was comprised of two distinct parts: papillary (P) and solid (S); B: The boundary between the papillary (right) and solid (left) areas. The papillary area consisted of a papillary proliferation of cholangiocyte-like columnar epithelial cells covering fine fibrovascular cores (arrows). In the solid area, a lacunar tumor was evident, but lacked distinct acinar/glandular structures. Magnification: × 100; C: The solid tumor at higher magnification. Tumor cells exhibited characteristic salt-and-pepper nuclei, a high nucleus-to-cytoplasm ratio, and increased nuclear chromatin. Magnification: × 400.

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.