Introduction Low-grade malignant fibrogenic tumor of bone Epidemiology incidence extremely rare demographics usually occurs in adolescence and young adults (15-25) body location mandible and metaphysis of long bones Prognosis recurrence rate of 40% Symptoms Presentation painful lesion Imaging Radiographs findings purely lytic lesion soap bubble appearance (internal pseudotrabeculatins) endosteal scalloping may involve cortex may have soft tissue mass Histology Classic characteristics are dense swirling fibrous spindle cells mature fibroblasts without cellular atypia abundant bundles of collagen Treatment Operative wide surgical resection vs. intralesional curretage indications wide surgical resection recommended to avoid recurrence Location Xray Xray CT B. Scan MRI Histo(1) Case A distal tibia Case B proximal tibia Case C distal femur (1) - histology does not always correspond to case