Clinicopathological characteristics of intrahepatic cholangiocellular carcinoma presenting intrahepatic bile duct growth

Background: Intrahepatic cholangiocellular carcinoma (ICC) presenting intraductal growth (IG) has distinct clinicopathological features with a favorable prognosis. The mass-forming (MF) plus IG type of ICC has not been previously investigated. Methods: One hundred forty-four patients with ICC underwent surgical resections and were classified according to the macroscopic type. The clinicopathological features of the IG type (n=7) and MF plus IG type (n=14) were retrospectively analyzed. The clinicopathological differences between the MF plus IG type and MF plus periductal infiltrating (PI) type (n=37) were compared. Results: All of the patients with the IG type had no sign of recurrence and survived. The 5-year overall survival rates was significantly better in the MF plus IG type than in the MF plus PI type (41.3% vs. 13.3%, P=0.034). Significant differences were recognized between the MF plus IG type and MF plus PI type, in terms of vascular resection (P=0.030), mucosal extension (P=0.006), and postoperative recurrence (P=0.004). Conclusions: The MF plus IG type had significantly better prognosis than the MF plus PI type. The IG type and MF plus IG type should be distinguished from other types even if hepatic hilar confluence is involved, because of the favorable outcome after surgery.