Osteoid osteoma: MR imaging of two untreated lesions.

Nonoperative management is currently the preferred method of treatment for osteoid osteoma by some orthopedic surgeons. The follow-up imaging appearance of osteoid osteoma in patients who are managed conservatively has not previously been described in radiology literature, and it is unclear what the natural evolution of the imaging findings is. Such patients may present to the radiologist either for follow-up assessment of the lesion or as an incidental finding during imaging for an unrelated complaint. The magnetic resonance imaging (MRI) findings in two patients with osteoid osteoma who underwent conservative treatment are presented.