Immunohistochemical evaluation of a sarcomatoid hepatocellular carcinoma with osteoclastlike giant cells

BACKGROUND Malignant liver tumors with osteoclast-like giant cells are rare. A literature search showed 17 previously reported cases that included the following: (1) 8 undifferentiated hepatocellular carcinomas, (2) 5 sarcomatous tumors with osteoclast-like giant cells associated with intrahepatic cholangiocarcinoma or liver cystadenocarcinoma, and (3) 4 sarcomatoid tumors with osteoclast-like giant cells associated with areas of a conventional hepatocellular carcinoma. CASE PRESENTATION A 68-year-old man presented with a tumor of the right lobe of the liver on ultrasonography and computed tomography. Laparoscopy showed a tumor (diameter, 4 cm) in segments 7 and 8 of the right liver lobe that adhered to the retroperitoneum. The tumor recurred 3 months after liver segmentectomy. Repeat laparoscopy showed diffuse and nodular metastases to the omentum and peritoneum. RESULT Light microscopy showed that part of the tumor had features of classic hepatocellular carcinoma. Another part of the tumor had a solid sarcomatous pattern with osteoclast-like giant cells that were irregularly distributed between the smaller undifferentiated tumor cells; cells of this part of the tumor were positive for heppar-1. CONCLUSION Light microscopic findings including osteoclast-like giant cells, and the strong reaction of heppar-1 antibody with cells of the sarcomatous part of the tumor, confirmed that this sarcomatous element was a metaplastic or transformed portion of hepatocellular carcinoma. VIRTUAL SLIDES The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/6000512901462616.