MALIGNANT FIBROUS HISTIOCYTOMA OF BONE AND SOFT-TISSUE - 2 DIFFERENT TUMOR ENTITIES - A RETROSPECTIVE STUDY OF 45 CASES

Background: Malignant fibrous histiocytoma (MFH) can arise as primary bone or soft-tissue sarcoma. Primary MFH of bone and soft tissue are h istopathologically indistinguishable. The aim of the study was to asse ss the clinical course and oncological outcome of MFH of bone and soft tissue. Methods: 45 patients with a confirmed diagnosis of MFH (25 pr imary bone MFH, 20 primary soft-tissue MFH) were seen between 1974 and 1993 in our institution. Patient records, pathology, and operation re ports were assessed for staging and oncological outcome with respect t o differences in clinical behavior and response to chemo- and radiothe rapy. Follow-up was more than 36 months in 33 patients. Results: MFH o f bone metastasizes more frequently and earlier and responds better to chemotherapy than MFH of soft tissue. Soft-tissue MFH has a higher lo cal recurrence rate, and local control can only be achieved by adequat e resection margins. 3-year tumor-free survival in our series is 21% f or bone and 57% for soft-tissue MFH. Conclusion: With respect to clini cal behavior MFH of bone and MFH of soft tissue can be considered as 2 different tumorentities. The reason for this remains unclear. In the authors opinion MFH of bone should be treated with chemotherapy and su rgery.