Figure 3. Images of the patient discussed in case three.

Repeat radiographs of the ankle performed at our institution three months after initial presentation to outside health care provider (A, B) which showed a small sclerotic area in the anterior talus. MRI (sagittal (C) and axial (D) inversion recovery, and sagittal (E) and axial (F) proton density) showed a low-signal area with surrounding edema, consistent with osteoid osteoma. RFA was successfully performed on the lesion under CT guidance (G, H).

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