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![Primary malignant tumors of bone surface: a review with emphasis in differential diagnosis](https://image.oaes.cc/4f8d375d-83b7-45e8-b9f3-0673d41b4f2f/3818.fig.3.jpg)
Figure 3. X-rays of distal femur exhibiting an exophytic and sclerotic mass projecting from the cortex in its popliteal fossa (A); Gross specimen of parosteal osteosarcoma, encircling the femur with a gritty cut surface (B); Characteristic microscopic arrangement of parallel bone trabecula and the intervening low-grade fibroblastic component (H&E; 50X) (C); MDM2 nuclear positivity (IHC; 50X) (D)