Clinical and pathological features of Allen's type C classification of resected combined hepatocellular and cholangiocarcinoma: a comparative study with hepatocellular carcinoma and cholangiocellular carcinoma.

The clinical features of Allen's type C of combined hepatocellular and cholangiocarcinoma (cHCC-CC) are not well known. In this study, we aim to define the clinicopathologic features of cHCC-CC and to evaluate the preoperative diagnosis and surgical treatment results in comparison with those of hepatocellular carcinoma (HCC) and cholangiocellular carcinoma (CCC). We retrospectively analyzed 13 patients with cHCC-CC, 509 patients with HCC, and 41 patients with CCC treated in our hospital within past two decades. Viral hepatitis B or C backgrounds were more prominent in HCC and cHCC-CC groups than in the CCC group. Elevated serum alpha-fetoprotein (AFP) levels were found in 60.3% of HCC patients and in 46.2% of cHCC-CC patients. Only one patient of cHCC-CC was correctly diagnosed before surgery. The postoperative survival rates between the cHCC-CC and HCC or the CCC group were not significantly different. Both intrahepatic and extrahepatic postoperative recurrences were frequent in cHCC-CC patients, and CCC component recurrences were more frequently seen. In conclusion, the preoperative diagnosis is difficult; liver masses similar to those of HCC, together with moderately elevated serum AFP and CA19-9 levels, are reliable indicators of cHCC-CC. Surgical resection of this tumor yields results intermediate between those of HCC and CCC in character. More cases are needed to further define the characteristics of this tumor.