Osteoid osteoma of the femur with a double nidus: a case report.

Osteoid osteoma is a common benign lesion, that occurs in children and young adults. The authors report the observation of a multifocal lesion which is infrequently reported in the literature. S.A., a 10-year-old female came to our observation complaining of spontaneous pain in her right hip and cruralgia radiating to the homolateral knee over the last 6 months; the symptoms, which increased during the night, were relieved by treatment with NSAIDS. Clinical examination and imaging studies confirmed a diagnosis of osteoid osteoma with a double nidus; the lesion was treated by CT-guided thermo-ablation with radiofrequency under general anaesthesia. Complete regression of symptoms was observed at 2-year follow-up.