Endoscopic biliary imaging and clinicopathological features of cystic duct cancer

Background: Cystic duct cancer fulfilling Farrar's criteria is relatively rare, but tumors whose origin is estimated to be in the cystic duct exist. The clinical features of such "broadly defined" cystic duct cancer have not been clarified. Methods: The endoscopic retrograde cholangiography (ERC) findings, intraductal ultrasonography (IDUS) findings, histological findings, and prognoses of 11 cases of cystic duct cancers resected at our institution (group C) were retrospectively analyzed. As a control group, 55 cases of middle or lower bile duct cancer (group B) were used (in 20 of the 55 cases of group B, tumors extended to the cystic duct intraluminally (group B-C (+)). Results: (1) ERC findings of group C as compared with those of group B-C (+) were as follows: (a) unilateral bile duct narrowing (spoon-like appearance): 55% versus 5% (P < 0.01); (b) bilateral bile duct narrowing (apple-core-like appearance): 27% versus 95% (P < 0.001). (2) IDUS was unable to visualize the cysticocholedochal junction (negative ";confluence sign") more often in group C (67%) than in group B-C (+) (13%) (P < 0.01). (3) Histologically, tumors extended to the gallbladder and the bile duct in 36% and 91% of the cases in group C, respectively. (4) The median survival time of the two groups was 21 and 28 months, respectively. Conclusions: Cystic duct cancers frequently extended to the bile duct. The spoon-like appearance by ERC and the negative confluence sign by IDUS were characteristic findings.