PMC5548340_01
a: Abdominal computed tomography (CT) indicates mass formation at the part of communication of cystic, common hepatic and common bile duct (white arrow).. b: Magnetic resonance cholangiopancreatography (MRCP) reveals dilation of the common bile duct and signal defects. (white arrow).. c: Endoscopic ultrasonography (EUS) reveals a mass in the cystic duct extending to common bile duct (white arrow).. d: Endoscopic retrograde cholangiopancreatography (ERCP) shows a filling defects in the communication of cystic, common hepatic and common bile duct (white arrow).
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Abdominal contrast enhanced computed tomography (CT) imaging revealed a tumor located in the communication of three ducts (the cystic, common hepatic, and common bile ducts), as well as dilation of the common hepatic and intrahepatic bile ducts (Fig. 1-a). T2-weighted images (Fig. 1-b). The tumor was 1.0 x 0.8 cm in size. The CT showed that the tumor was highly enhanced in the arterial phase, and this enhancement pattern was prolonged in the delay phase. The range of horizontal extension of the tumor was considered to be from the part of communication of the main hepatic duct to the middle bile duct (Fig. 1-c and d).
Histological findings.. a: A tumor was located in the cystic duct (white arrow) and common biliary duct (red cicle).. b, c: On the surface of the tumor, cells represent well-differentiated adenocarcinoma. The infiltrative tumor comprises neuroendocrine carcinoma (H.E. staining).
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Macroscopically, the tumor was mainly located from the cystic duct to the common biliary duct (Fig. 2-a). In the invasive area, the tumor cells with hyperchromatic nuclei and scant cytoplasm were spread (Fig. 2-b and c).
Immunohistochemically findings.. The tumor cells were diffusely positive for chromogranin A (a), synaptophysin (b), CD56 (c). The Ki-67 positive cells were around 80.0% (d).
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These findings were consistent with neuroendocrine carcinoma according to the WHO criteria for the clinicopathologic classification of neuroendocrine tumors (Fig. 3).