Combined hepatocellular carcinoma and osteoclast‐like giant cell tumor of the liver: Possible clue to histogenesis

Abstract

Hepatic giant cell tumor is extremely rare, and only five cases have been reported of overt hepatocellular carcinoma, thus its histogenesis is controversial. Herein is reported a case of simultaneous hepatocellular carcinoma and osteoclast-like giant cell tumor in a single tumor. A liver tumor was found in a 74-year-old woman. Histologically the tumor consisted of two distinct components: mononuclear and multinuclear giant cells with osteoclastic giant cells, and a conventional hepatocellular carcinoma. The boundary between the two components showed transitional features. Immunohistochemistry showed that the osteoclast-like giant cells were CD68 and vimentin positive, but cytokeratin and AFP negative, while spindle-shaped cells were positive only for vimentin. In a portion of the hepatocellular carcinoma the cells were cytokeratin-8 and AFP positive. Ki-67 positivity was 10% for the hepatocellular carcinoma, 60% for the spindle-shaped cells, and 0% for the giant cells. It is possible that the tumor might have had a hepatocellular carcinoma origin, given the more highly proliferative sarcomatous changes and reactive osteoclast-like cells. This case provides a clue to the histogenesis of hepatic giant cell tumors.