[Malignant giant cell tumor of soft tissue]

Clinical, pathologic, and electron microscopic study of 4 cases of malignant giant cell tumor of soft tissues is presented. Conventional histology and electron microscopy disclosed histiocyte-, fibroblast- and osteoclast-like multinucleated giant cells, cells with 2 and 3 nuclei, and undifferentiated cells. Malignant giant cell tumor of soft tissues is therefore considered to be a special variant of malignant fibrous histiocytoma.