Misdiagnosed iuxta-articular osteoid osteoma of the calcaneus following an injury.

The diagnosis of osteoid osteoma, in usual localizations, is generally simple. In iuxta-articular localizations this tumor may be unrecognized and the diagnosis delayed. Injury has been sometimes correlated with the onset of symptoms and this can make the diagnosis even more difficult. We present a case of osteoid osteoma of the calcaneus iuxta-articular to the subtalar joint in a 17-year-old basketball player. He had a history of initial injury, ankle sprain during training, followed by pain and swelling. He was initially treated for lateral ligament lesion of the ankle with unsatisfactory results. After acute trauma the pain changed becoming chronic and mostly nocturnal disappearing when rofecoxib was taken. Standard x-ray didn't show the lesion. Nuclear Magnetic Resonance (NMR) and scintigraphic results were not well interpreted but these clinical changes and Computed Tomography (CT) images supported the diagnosis of osteoid osteoma. The complete resection of the bone lesion resolved all the symptoms and the histological report confirmed the suspected diagnosis.