Undiff. Pleomorphic Sarcoma : Giant Cells
Some cases of undifferentiated pleomorphic sarcoma (UPS) have numerous multinucleated, osteoclast-type giant cells. This entity was previously called giant cell MFH or malignant giant cell tumor of soft parts. The tumor has a multinodular architecture, with dense fibrovascular bands separating individual nodules. Hemorrhage and necrosis are frequent. The nodules are composed of spindled, epithelioid, and osteoclast-type giant cells. There is significant pleomorphism with increased mitotic activity. The periphery of the nodules may contain osteoid or mature bone.