SUMMARY Fibrosarcoma of Bone is a malignant, high-grade, fibrogenic tumor of bone that usually occurs in patients > 50 years of age who presents with regional pain and swelling. Diagnosis is made with a biopsy and histology showing atypical spindle cells in a herringbone pattern. Treatment is usually wide surgical resection and multiagent chemotherapy. Prognosis Prognosis is poor high grade has 30% survival at 5 years majority are high-grade low grade has 80% survival at 10 years PRESENTATION Symptoms pain and swelling Imaging Radiographic characteristics purely lytic lesion with bone destruction in a permeative pattern ill defined features looks like osteosarcoma Bone scan is very hot STUDIES Histology Same as soft tissue sarcoma atypical spindle cells herringbone pattern variable levels of collagen production Treatment Operative wide surgical resection and multiagent chemotherapy indications all malignant cases chemotherapy multiagent chemotherapy only if high grade (most cases)