World Health Organization classification of bone and soft tissue tumors: modifications and implications for radiologists.

The working group of the World Health Organization (WHO) for classification of tumors of soft tissue and bone met in 2002. The consensus of this conference led to modifications in the nomenclature primarily for soft tissue neoplasm, leaving osseous tumors largely unaltered. The most significant changes in nomenclature involved the group of fibrous and lipomatous malignancies. This article reviews the modifications of this nomenclature and the justification for these changes. The WHO suggested replacement of the term MALIGNANT FIBROUS HISTIOCYTOMA (MFH) with undifferentiated high-grade pleomorphic sarcoma and combining myxoid and round cell liposarcoma under the umbrella of myxoid liposarcoma. The imaging appearances of the fibrous and lipomatous malignancies is reviewed and emphasized in this article. It is important for radiologists involved in evaluation of these lesions to have an understanding of the current nomenclature. This allows improved uniformity in our discussions with pathologists and orthopedic oncologists in our team approach in the diagnosis and treatment of these patients.