Low-grade central osteosarcoma of distal femur, resembling fibrous dysplasia

Figure 4 Open biopsy was performed obtaining bone specimens from the outer lateral condyle with 3 cm × 2 cm × 1 cm total dimensions. A: Excised specimen of the distal 15.5 cm of the femur. Compressive fracture of the posterior cortex (arrows); B: The tumor arose within the medullary cavity and extended from the cartilage surface to 3 cm distance from the excision line. The mass clearly breaches the cortex (arrow); C: Hinged custom made total knee arthroplasty (Howmedica Modular Resection System, Stryker Howmedica Osteonics, Inc).