Osteoid osteoma causing subtalar joint arthralgia: a case report.

Abstract

The authors describe a juvenile patient with an osteoid osteoma in the foot-a relatively rare location for this type of lesion. The appearance of this lesion in a juxtaarticular location is even more rare. An 11-year-old boy with a 6-month history of limping secondary to subtalar joint pain presented with a juxtaarticular osteoid osteoma located within the calcaneus. The lesion was present beneath the sinus tarsi and the subtalar joint region. Plain radiographs showed equivocal changes; however, magnetic resonance imaging clearly showed a central nidus. The lateral aspect and midbody of the calcaneus showed a spherical focus of diminished signal on both the T1- and T2-weighted images. This focus had a surrounding rim of significantly diminished signal on all sequences. Thus, findings were most consistent with an osteoid osteoma, although a Brodie abscess could not be ruled out. Surgical excision was performed and led to complete resolution of pain and limping. The pathology report confirmed the diagnosis of osteoid osteoma.