summary Pleomorphic Sarcoma of Bone, formerly known as Malignant Fibrous Histiocytoma, are rare malignant histiocytic lesions of bone most commonly found in the metaphysis of long bones. Patients typically present between the ages of 20 to 80 with painful, regional masses. Diagnosis is made with biopsy showing pleomorphic spindle cells and histiocytic cells in storiform pattern. Treatment is usually neo-adjuvant chemotherapy, limb salvage surgical resection, followed by adjuvant chemotherapy Epidemiology Incidence comprises < 2% of all primary malignant bone tumors second most common bone sarcoma in adults after chondrosarcoma Demographics affects individuals 20 to 80 years of age highest rates of affected patients in 2nd to 4th decades male > female (3:2) more common in Caucasians than African Americans or Asians Anatomic location 75% of cases from appendicular skeleton often metaphysis of long bones primarily distal femur, proximal tibia, proximal humerus Risk factors 25% arise as secondary lesion from bone infarct, Paget disease, or prior radiation Etiology Genetics mutations of the tumor suppressor gene p53 have been implicated in tumorgenesis of secondary MFH of bone Presentation History new, painful mass can present with pathologic fracture Symptoms pain constitutional symptoms fevers, chills, night sweats and weight loss Physical exam inspection swelling limp motion decreased range of motion Imaging Radiographs recommended views AP and lateral of affected area findings lytic and destructive lesion often in the metaphysis variable periosteal reaction cortical destruction with soft tissue extension radiographs often non-specific MRI indications necessary to better characterize lesion findings deep seated heterogeneous mass often associated with internal hemorrhage T1- low signal T2- high signal CT scan indications CT chest used for staging to assess for pulmonary mets to assess the amount and character of bone destruction Bone scan indications may be ordered as part of pre-treatment staging findings shows increased uptake in adjacent cortex Studies Labs elevated WBC eosinophilia abnormal LFTs hypoglycemia Histology pleomorphic spindle cells and histiocytic cells in storiform pattern malignant multinucleated giant cells with grooved or indented nuclei areas of chronic inflammatory cells variable collagen production fibrous fascicles radiate from focal hypocellular areas hemorrhagic and necrotic regions not infrequent; suggest high-grade lesion Differential Differential of Pleomorphic Sarcoma of Bone Malignant destructive lesion in older patient Sacral lesions in older patients Treated with wide resection and chemotherapy MFH / fibrosarcoma o o o Chondrosarcoma o o Dedifferentiated chondrosarcoma o o o Metastatic disease o o Lymphoma o o Myeloma o o Secondary sarcoma o o o Osteosarcoma o Chordoma o Ewing's o Rhabdomyosarcoma (soft tissue) o Treatment Operative(similar to osteosarcoma) neoadjuvant chemotherapy, wide resection, postoperative chemotherapy +/- radiation indications standard of care chemotherapy preoperative chemotherapy given for 8-12 weeks followed by maintenance chemotherapy for 6-12 months after surgical resection surgical resection correct surgical option is based on the location of the tumor and the feasibility of obtaining a wide surgical margin wide excision or amputation have been found to have a higher 5-year survival rate than those who received intralesional or marginal excision trend towards limb salvage whenever possible options include endoprosthetic arthroplasty, resection arthrodesis, allograft reconstruction and rotationplasty radiation indications incomplete or questionable margins in order to reduce risk of local recurrence adjunct to traditional chemotherapy and surgical regimens Prognosis 50% - 60% survival at 5 years Worse prognosis with secondary MFH compared to primary lesions Pulmonary metastasis common in up to 30% Good response (> 90% tumor necrosis) to neoadjuvant chemotherapy found to have a much better prognosis Age younger than 40 years associated with improved disease-free survival rate