PMC4727081_01
(A) Computed tomography revealed slight dilation of the common bile duct, with a mass in the distal common bile duct (revealed by the arrow). (B) Endoscopic retrograde cholangiopancreatography revealed a 25 mm fixed filling defect in the distal common bile duct (indicated by the arrows). (C) Intraductal ultrasonography revealed an iso-high echoic mass in the distal bile duct (indicated by the arrows). (D) Fluorine-18 fluorodeoxyglucose positron emission tomography demonstrated an increased accumulation of tracer in the distal bile duct, with a maximum standard uptake value (SUVmax) of 3.3 (highlighted by the arrow).
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Computerized tomography (CT) revealed a slight dilation of the CBD, with the identification of a mass in the distal CBD (Fig. 1A). Radiological examinations revealed the presence of a 25 mm fixed filling defect in the distal CBD, and intraductal ultrasonography revealed an isoechoic, and partially high echoic, mass (Figs. 1B and C). A biopsy of this lesion revealed the presence of tubular adenoma with low-grade atypia. 18F-FDG PET demonstrated an accumulation of focal increased tracer in this lesion, with a maximum standard uptake value (SUVmax) of 3.3, and the position where uptake of the 18F-FDG occurred was separate from the drainage tube (Fig. 1D).
Surgical specimen and histological findings. (A) A macroscopic view of the resected specimen. A polypoid tumor is impacted in the intrapancreatic bile duct. (B) A low-power view (magnification x12.5) revealed that the intraductal neoplasm resided in the lumen. Neither necrotic foci nor invasion in the duct wall were observed. (C) The highest-power view (magnification x100) revealed that the tubules were relatively uniform, composed of cells of bland appearance. Nuclear stratification, nuclear pleomorphism and mitotic figures were not observed.
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The tumor was impacted in the bile duct lumen, occupying 2.5 cm in length (Fig. 2A). Furthermore, invasion was not observed in the duct wall, and no intraductal mass was identified (Fig. 2B and C).