We report here on a case of combined hepatocellular and cholangiocarcinoma (CHC) with neuroendocrine differentiation and sarcomatoid transformation. A 59-year-old male who had had HBV-associated chronic liver disease presented with hepatic masses. The explanted liver showed three small masses, two in the right lobe and one in the left lobe. The largest one in the right lobe was a 2.0 cm sized binodular mass,consisting of a yellowish tan nodule and an abutting reddish brown nodule. Microscopically, the reddish brown nodule was a cholangiocarcinoma (CC) showing neuroendocrine differentiation and sarcomatoid tranformation. The yellowish tan nodule and the remaining two masses were hepatocellular carcinoma (HCC)s. On immunohistochemistry, both the adenocarcinoma and spindle sarcomatoid cells were positive for pancytokeratin, but only the adenocarcinoma cells were positive for chromogranin and carcinoembryonic antigen (CEA). Mitotic and Ki67 labeling indices as well as p53 immunopositivity were significantly increased only in the CC component. We report here on the first case of CHC in which the CC displayed neuroendocrine differentiation and sarcomatoid transformation with high mitotic and Ki67-labeling indices, as well as having p53 overexpression.
Eight cases of combine hepatocellular-cholangiocarcinoma(HCC-CC) of the liver were analysed along with their growth patterns and histologic subtypes to draw a possible implication in understanding of their histogenesis. The relative incidence of combined HCC-CC among the surgically resected primary carcinomas of the liver(485 cases) was 1.6%. The combination patterns varied and were classified as follows; the multinodular tumor, each consisting of HCC or CC element(type 1) was found in 1 case, the single tumor mass with two distinct compartments of HCC and CC(type 2) in 3, and the single tumor with random mixture of two elements(type 3) comprised the remaining 4 cases. Of the 7 cases of single tumor mass(type 2 and 3) HCC and CC comprised the major component in 5 and 2 cases, respectively. The histologic features of both HCC and CC elements were not different from those of isolated HCC and CC, except for two of CC element in type 3 which disclosed the intermediated differentiation or socalled cholangiolocellular carcinoma in part. We conclude that there is no significant difference in the relative incidence of combined HCC-CC among primary carcinomas of the liver and their subtypes compared to that in other countries, regardless of high incidence of both HCC and CC in Korea. Also, we discussed a possible histogenisis along a hypothesis that some of the combined HCC-CC be the consequence of interposition of different cell type from a new subclone into the growth of an initial single cell type of primary carcinoma of the liver.