A cholangiocarcinoma of the hepatic hilus with an element of giant cell tumor that occurred in a 59-year-old man is reported. His medical history included systemic cholelithiasis and repeated operations on the biliary passages. Four years after the last operation, which was a hepatic segmentectomy, he was readmitted because of persistent fever. A computed tomography scan showed a low-density area and stones in the hepatic hilus. He died of hepatic failure approximately 1 month later. At autopsy, a fist-sized tumor and gallstones were found at the hepatic hilus. Histologically, the tumor mainly showed sarcomatoid features and some tubular adenocarcinoma. An element of giant cell tumor consisting of many osteoclast-type giant cells also was noted. The results of immunohistochemical studies showed a positive reaction to cytokeratin and vimentin in some of the spindle-shaped sarcomatoid cells. Sarcomatoid bile duct carcinomas are rare, as are those with osteoclast-type giant cells. The authors also discuss the histogenesis of these giant cells. Cancer 1992: 69:2444-2448.
Sarcomatoid features are occasionally seen in various types of epithelial tumors,'-3 and sometimes it is difficult to differentiate between sarcomatoid carcinoma and true sarcoma. Most sarcomatoid carcinomas in the liver are thought to be sarcomatoid hepatocellular carcin o m a ~. * ~~ In one rare case of hepatocellular carcinoma, numerous osteoclast-type giant cells were detected in addition to a sarcomatoid pattern6
Although many adenocarcinomas with sarcomatoid features have been reported, sarcomatoid dediffer-