Figure 2. Images of the patient discussed in case two.

Initial AP (A) and lateral (B) weight-bearing radiographs of the patient in case two were normal. The osteoid osteoma was identified on MRI and is highlighted by the lesion shown on the axial T1 (C) and fluid sensitive (D) sequences; extensive edema around the lesion was seen on the sagittal inversion recovery sequence (E). The nidus of the osteoid osteoma is seen on the CT axial (F), coronal (G), and sagittal (H) images. RFA localization of the lesion via CT is shown in I and J.

MRI: magnetic resonance imaging; CT: computed tomography; RFA: radio-frequency ablation