Osteoid osteoma mimicking chronic arthritis. Diagnosis by bone scintigraphy.

The case of a patient with osteoid osteoma of the heel is presented. The patient was misdiagnosed and treated for four years as having arthritis. Osteoid osteoma was diagnosed by 99mTc-MDP bone scan that was performed for the evaluation of the arthritis. Plain radiography and magnetic resonance imaging (MRI) were negative for signs of arthritis. However, MRI when reevaluated after positive bone scintigraphy, was found positive for osteoid osteoma. This case underscores the value of bone scintigraphy for the diagnosis of osteoid osteoma.