Pleomorphic liposarcoma of bone: a rare primary malignant bone tumour

Figures

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  Fig. 1. a AP and lateral b plain radiographs demonstrate an ill-defined radiolucent lesion in the proximal tibial metadiaphysis (black arrows) with posteromedial cortical destruction and adjacent ossification (black arrowheads). A medial soft tissue mass with low density raises the possibility of a fatty matrix (white arrow). A pathological fracture is present (white arrowhead)

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  Fig. 2. Magnetic Resonance Imaging (MRI) of the proximal tibial lesion. a Coronal STIR, b coronal T1-, c axial T1-, d axial T2-weighted and, e axial proton density with fat saturation. The images demonstrate an ill-defined proximal tibial medullary based lesion extending to the subarticular surface. There is extensive cortical destruction with an almost circumferential soft tissue mass, which has a spiculated appearance (black arrows) displacing the posterior muscles and popliteal neurovascular bundle. Tumour breaches the deep fascia anteriorly to extend into the subcutaneous tissues and penetrates the interosseous membrane to extend around the anterolateral tibial cortex. Heterogeneous partly high T1 signal suppresses with fat saturation sequences supporting a partly fatty matrix (white arrowheads). The pathological fracture is clearly seen extending transversely across the proximal tibia (white arrows)

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  Fig. 3. Axial CT and PET/CT imaging of the proximal tibial lesion. a Axial CT imaging shows medial cortical destruction and a large soft tissue mass containing areas of fat attenuation (white arrowheads) and ossification (black arrows). b A coronal fused PET/CT image shows there is marked FDG uptake in the proximal tibial tumour as well as in a lateral distal femoral metastasis (white arrow). No other lipomatous lesion or tumour is present

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  Fig. 4. Histological analysis of the proximal tibial lesion shows primary pleomorphic liposarcoma of bone. a The tumor infiltrates cancellous bone and is composed of numerous lipoblasts and large pleomorphic cells, which have vacuolated cytoplasm and atypical nuclei. b Lipoblasts and brown fat-like cells are seen within the tumour. Immunohistochemistry shows the tumor cells express FABP4/aP2 (c) and UCP1 (d)

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  Fig. 5. Post-resection AP plain radiograph demonstrates a Stanmore prosthesis with integral distal femur and modular proximal tibial component