Case report: intrahepatic cholangiocarcinoma with rhabdoid transformation.

Sarcomatous transformation is found in approximately 5% of patients with intrahepatic cholangiocarcinoma. According to previous reports, sarcomatous cholangiocarcinomas are composed of spindle-shaped cells and/or multinucleated giant cells. Usually, vimentin is expressed by these sarcomatoid cells. We report a case of intrahepatic cholangiocarcinoma with an element of rhabdoid cells that occurred in a 61-year-old woman admitted for back pain. Various imaging techniques demonstrated multiple liver masses. Histologically, these tumours formed in both sarcomatous and ordinary tubular adenocarcinomatous areas. The sarcomatoid areas were occupied mainly by loosely arranged, eosinophilic rhabdoid cells, which expressed both keratin and vimentin. These findings suggest that rhabdoid cells may occur in an undifferentiated stage of cholangiocarcinoma and possess a strong tendency to metastasize.