An autopsy case of hepatic sarcomatoid tumor: immunohistochemical comparison with a sarcomatous component of hepatocellular carcinoma.

A case of primary hepatic tumor exclusively composed of malignant cells with sarcomatous features is described and compared immunohistochemically with two cases of hepatocellular carcinoma (HCC) with a sarcomatous component. More than 30% of HCC cells were positively stained with anti-cytokeratin (CAM5.2), anti-albumin, anti-fibrinogen and anti-alpha 1-antitrypsin antibodies, and some with anti-epithelial membrane antigen. The present sarcomatoid tumor and the sarcomatous component with HCC showed similar immunohistochemistry; many tumor cells were strongly immunoreactive for vimentin and some positive for cytokeratin, albumin, fibrinogen and alpha 1-antitrypsin. Other immunohistochemical markers, indicating specific differentiations to lineage of macrophages, muscle cells, glial cells, endothelial cells and so forth, were not detected in sarcomatous tumor cells of all cases. These findings suggest that the present sarcomatoid tumor would belong to an anaplastic sarcomatous variant of HCC.