Intrahepatic cholangiocarcinoma with sarcomatous transformation: an autopsy case.

We report an adult case of intrahepatic cholangiocarcinoma with remarkable sarcomatous changes. At autopsy a yellowish-white tumor (8 x 6 cm) was found in the left hepatic lobe, and there were several daughter nodules in both hepatic lobes. Histologically, most of the main tumor, and all of the daughter nodules examined, showed sarcomatous changes (spindle- or fusiform-shaped and pleomorphic cells). Histologic examination of a whole slice of the main tumor disclosed a focus of adenosquamous carcinoma (cholangiocarcinoma) within the tumor. Frequent transitions between adenosquamous carcinoma areas and sarcomatous areas suggested that sarcomatous transformation occurred in cholangiocarcinoma and then grew to spread rapidly. Immunohistochemically, squamous carcinoma and, to a lesser degree, adenocarcinoma elements were strongly positive for keratin and epithelial membrane antigen, both being also weakly positive in sarcomatous cells, supporting that possibility. Vimentin was positive only in sarcomatous elements. Cholangiocarcinoma should be included in the list of hepatic tumors showing sarcomatous change.