Giant Cholangiolocellular Carcinoma With Early Recurrence That Was Difficult to Distinguish From Cholangiocellular Carcinoma: Report of a Case.

Cholangiolocellular carcinoma (CoCC) is a rare type of malignant liver tumor derived from hepatic stem cells, which exist in the canals of Hering. However, the characteristics of CoCC have not been clarified. In general, CoCC is associated with a better prognosis than cholangiocellular carcinoma (CCC). Here, we report a case of giant CoCC, which was difficult to distinguish from CCC and showed early recurrence and necrosis inside the tumor. A 59-year-old man was diagnosed with CCC based on preoperative imaging. The diameter of the tumor was approximately 14 cm, and he subsequently underwent extended right lobectomy of the liver. Histopathologic analysis revealed that tumor cells proliferated and replaced the surrounding normal liver cell cords in front of the tumor. Furthermore, the tumor cells were positive for cytokeratin 19 and epithelial membrane antigen. Epithelial membrane antigen staining pattern was positive on the membranous area of the lumen. Therefore, the tumor was diagnosed as CoCC. Although adjuvant chemotherapy was performed, intrahepatic recurrence occurred at 4 months after surgery. We present here the novel characteristics of CoCC that show early recurrence and necrosis within the tumor. These characteristics have not previously been reported in patients with CoCC.