PMC6013685_01
Abdominal and pelvic computed tomography showing a complex gallbladder mass with extension into the right hepatic segment (arrow).
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F1
A computed tomography (CT) scan of the abdomen and pelvis showed a complex mass (8.5 x 7.2 x 10.8 cm) within the gallbladder fossa with intrahepatic extension concerning for malignancy (Figure 1).
Hematoxylin and eosin (H&E) stain of fine-needle aspiration cytology and cell block showing small to large cells with a high nuclear-to-cytoplasmic ratio and round nuclei with an open, salt-and-pepper chromatin pattern present singly or forming rare clusters or micro-rosettes (x400).
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F2
Biopsies obtained with fine-needle aspiration were fixed in formalin for hematoxylin and eosin (H&E) stain and immunohistochemistry stain (Figure 2).
Tumor cells showing cytoplasmic positivity for (A) synaptophysin (x400) and (B) Ki67 (x200) with high Ki67 index (>90%) and nuclear positivity for Ki67.
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F3
Immunohistochemistry revealed cells positive for synaptophysin and CD56, with a Ki67 > 90%, and negative for chromogranin, CD45, and CD20, suggesting a high-grade neuroendocrine carcinoma (Figure 3).
Endoscopic retrograde cholangiopancreatography showing a Bismuth type IIIa stricture (arrow).
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F4
Endoscopic retrograde cholangiopancreatography revealed a Bismuth type IIIa stricture involving the primary branch of the right intrahepatic duct and extending to mid-common bile duct (CBD) (Figure 4).
H&E stain of tumor cells with intracytoplasmic mucin showing signet-cell morphology (arrows; x400).
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F5
Biliary duct biopsies revealed clusters of infiltrative tumor cells, mostly signet-ring cells; there were no visualized features of neuroendocrine carcinoma (Figure 5), and the biopsies were negative for synaptophysin and chromogranin.