What is the differential diagnosis?
Overall the appearances are off an aggressive lesion. The differentials include primary and secondary bone tumour including Ewing's sarcoma and metastasis. Further differentials include osteomyelitis as well as an 'aggressive osteoid osteoma' with secondary fracture.
Within the proximal metadiaphysis of the right femur, located eccentrically within the cortex is a lytic lesion measuring 2.7 cm with a central sclerotic focus. There is a permeative appearance to the lesion with a broad zone of transition as well as aggressive periosteal reaction. No definite soft tissue component is identified.