PMC5364192_01
Radiographic images of the extrahepatic bile duct tumor. A-C: Coronal plane of computed tomography (CT) images. A precontrast CT image (A) shows the extrahepatic bile duct mass (arrow) and the dilated gallbladder (arrowhead). The intrahepatic and extrahepatic bile ducts are dilated. A large renal cyst is present in the left kidney. An arterial phase CT image (B) shows that the mass has slight and heterogeneous enhancement. A delayed phase CT image (C) shows that the mass is further enhanced. D-E: Magnetic resonance imaging shows that the mass is heterogeneous and somewhat hypointense on a T1-weighted image (D) and partially hyperintense (arrow) on a T2-weighted image (E). The hyperintense area probably corresponds to the largest tumor. F: Sagittal plane of the ultrasonography image. An intraductal nodule 7 cm in length with dilatation of the extrahepatic bile duct is seen. The nodule includes a hypoechoic lesion (arrowheads) that probably corresponds to the largest tumor of four polypoid lesions. G: Percutaneous transhepatic cholangiography. A filling defect is seen in the extrahepatic bile duct. The paucity of the transverse portion of the duodenum suggests intestinal malrotation. White bar, 2 cm in A, D-G.
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Computed tomography (CT, Fig. 1A-C) and magnetic resonance imaging (MRI) showed a mass that was mainly located in the common bile duct, with marked dilatation of the intrahepatic bile ducts and the extrahepatic bile tract. A precontrast CT image (Fig. 1A) revealed that the intraductal mass was slightly hypodense relative to the hepatic parenchyma, with a mean Hounsfield units value of 38. An arterial-phase contrast-enhanced CT image (Fig. 1B) obtained 35 seconds after contrast administration demonstrated that the mass had a slight and heterogeneous enhancement pattern; the mean Hounsfield units value of the mass was 53. A delayed-phase contrast-enhanced CT image (Fig. 1C) obtained 90 seconds after contrast administration showed the mass to be more enhanced, with a mean Hounsfield units value of 65. MRI revealed that the mass was heterogeneous and somewhat hypointense relative to the bile duct wall on a T1-weighted image (Fig. 1D) and partially hyperintense on a T2-weighted image (Fig. 1E). Ultrasonography revealed a smooth mass with a maximum size of approximately 7 cm, in which a low echoic lesion 3 cm in diameter (Fig. 1F) was seen. Percutaneous transhepatic cholangiography as well as magnetic resonance cholangiopancreatography (MRCP) demonstrated that the extrahepatic bile duct lesion was a filling defect (Fig. 1G), and no pancreaticobiliary maljunction was observed.
The macroscopic and microscopic findings of the extrahepatic bile duct tumor. A: The macroscopic appearance of the formalin-fixed tissue. Four mural nodules (arrows) were present in the upper portion of the common bile duct. The cystic duct is indicated by arrowheads. B-F: Low to high magnification of the Hematoxylin and Eosin staining sections of the largest tumor. B: The largest mass showed a polypoid and solid lesion. C: The largest tumor mostly consisted of carcinoma cells in a trabecular growth pattern. D: Hyaline globules were present in some tumor cells. E: A tubular adenocarcinoma component was present at the base of the largest tumor. F: There was a transition between the trabecular and adenocarcinoma components. G-H: Immunohistochemistry findings. G: alpha-fetoprotein staining revealed diffuse positivity in the solid component (left) and no staining in the adenocarcinoma portion (right). H: Cytokeratin 7 staining was almost negative in the solid component (left) and diffusely positive in the tubular adenocarcinoma portion (right). Bar, 1 cm in A-B; 100 mum in C-H.
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After the intraductal materials were removed, a total 4 polypoid lesions with maximum diameters of 27 mm (Fig. 2A), 16 mm, 9 mm, and 8 mm were seen in the upper portion of the common bile duct. A pathological analysis revealed that the four polypoid lesions consisted of trabecular arrangements of polygonal cells with hyperchromatic nuclei and some central nucleoli(Fig. 2B and C). Hyaline globules (Fig. 2D) positive for Periodic acid Schiff staining with diastase treatment were present in the cytoplasm of some tumor cells. Well to moderately differentiated tubular adenocarcinoma (Fig. 2E) was confined to the base of the largest polypoid lesion and merged with the trabecular nests (Fig. 2F), while neither dysplastic epithelium nor tubular adenocarcinoma was present in the other smaller tumors or the surrounding biliary mucosa. An immunohistochemical analysis showed the poorly differentiated component to be positive for CAM5.2 (70%), cytokeratin 19 (CK19, 60%), AFP (95%, Fig. 2G), glypican-3 (70%), SALL4 (100%), hepatocyte paraffin 1 (HepPar1, 5%), CD10 (<5%, canalicular staining), and thyroid transcription factor-1 (dot-like cytoplasmic staining, <5%) and negative for CK7 (Fig. 2H), CK20, CA19-9, CEA, chromogranin A, synaptophysin, and CD56. The adenocarcinoma component showed diffuse immunoreactivity for CK7 (Fig. 2H), CK19, CEA, CA19-9, and CAM5.2 and was partially positive for CD10, but showed no immunoreactivity for CK20, SALL4, HCC markers, or neuroendocrine markers.