Osteoid osteoma of the acetabulum: a case report.

The acetabulum is a very rare location for osteoid osteoma. The diagnosis is difficult and usually delayed because the acetabulum is a rare site for this tumour and clinical signs are non-specific. Reported herein is the case of a 33-year-old woman who had non-specific pain and limitation of range of motion of the right hip. Bone scan, computed tomography and magnetic resonance imaging assessed the diagnosis of osteoid osteoma. Percutaneous resection guided by CTscan was performed and histology confirmed diagnosis. At follow-up, from two years, the patient remains asymptomatic. Osteoid osteoma of the acetabulum has been reported only in 13 cases. It is usually characterised by signs of synovitis. Recently, Computed Tomography guided percutaneous resection of OO has become the treatment of choice.