PMC4745865_01
Enhanced CT examination revealed dilatation of the intrahepatic bile duct in the left hemiliver.
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Contrast-enhanced computed tomography showed dilatation of the intrahepatic bile duct in the left hemiliver (Figure 1), and abdominal ultrasonography indicated the presence of a mass lesion in the left hepatic duct.
ERC revealed a filling defect within B3 (arrow).
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B3 (Figure 2), and biliary cytology showed class III cells. Based on these results, the patient was highly suspected of left side-dominated cholangiocarcinoma without hilar invasion; hence, we planned a laparoscopic surgical intervention with curative intent.
(a) The left branch of the portal vein was temporarily clamped so as to clarify a demarcation line. (b) The left hepatic vein was divided by an endoscopic linear stapler (arrow), and a cut surface along the middle hepatic vein was revealed.
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The left hepatic artery was then transected, and the left branch of the portal vein was dissected and temporarily clamped with a nonabsorbable clip (Hem-o-lok; Weck/Teleflex Medical, IL, USA) (Figure 3(a)). Flex 45 mm, open staple height 2.5 mm; Ethicon Endo-Surgery, Tokyo, Japan). Finally, the left hepatic vein was also divided with another endoscopic linear stapler (Figure 3(b)), and specimens were obtained from a 5 cm infraumbilical incision.
(a) Macroscopic findings of the resected specimens showed multiple cystic lesions surrounding the intrahepatic bile duct (arrow). (b) Multiple cystic dilatations of the extramural peribiliary glands with mucus production were observed (HE stain, x40). (c) Front formation on the BilIN was observed in the intrahepatic bile duct (HE stain, x400).
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Macroscopic findings of the resected specimens showed multiple cystic lesions surrounding the intrahepatic bile duct (Figure 4(a)). Microscopic findings using hematoxylin and eosin (HE) stain revealed multiple cystic dilatations of the extramural peribiliary glands with mucus production (Figure 4(b)); hence, this lesion was diagnosed as HPCs. The resected intrahepatic bile duct showed that the normal ductal lumen comprised low columnar epithelia; however, front formation on the BilIN was observed in some parts of the intrahepatic bile duct (Figure 4(c)).
(a) Both the BilIN and background epithelia were negative for MUC2. (b) Only BilIN was positive for MUC5AC. (c) Not only BilIN but also the background epithelia were positive for MUC6.
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Immunohistochemical staining of the BilIN revealed that it was positive for mucin (MUC) 5AC and MUC6 and negative for MUC2 (Figures 5(a)-5(c)). The background epithelia were positive for only MUC6 (Figure 5(c)).