Fig. 2

A 25-year-old man with osteoid osteoma of the left femur. a Preoperative anteroposterior plain radiographs do not indicate significant neoplastic lesions. b The preoperative axial-coronal CT image demonstrates a nidus of the proximal femoral (yellow arrow) with adjacent cortical thickening. c-e The intraprocedural bone biopsy under CT guidance. The intraprocedural axial CT image (using bone windows) shows that the biopsy needle is inserted into the bone lesion (yellow arrow). f-h The intraprocedural axial CT image shows the MWA antenna in the center of the lesion. i The histopathological biopsy results (hematoxylin and eosin, original magnification 100×) show scattered bone matrix osteoblasts in the tissue; calcification and fibrovascular proliferation were also observed