Intra-articular osteoid osteoma of the talar neck initially managed as early avascular necrosis: a case report

Abstract

Intra-articular osteoid osteoma is an uncommon benign osteoblastic tumor that frequently presents with atypical clinical and radiographic findings, often delaying diagnosis. Lesions involving the talus are challenging because marrow edema and synovitis may obscure the characteristic nidus on magnetic resonance imaging (MRI), mimicking other pathologic processes. We present the case of a young male with a greater than 2-year history of atraumatic ankle pain and diffuse talar marrow edema on MRI, initially interpreted as osteonecrosis. He underwent ankle arthroscopy and talar core decompression, with minimal improvement. Repeat MRI demonstrated an evolving dorsolateral talar neck lesion, raising concern for osteoid osteoma and prompting excision. Histopathology demonstrated osteoid osteoma. At 6-month follow-up, he reported full pain resolution and unrestricted activity. This case highlights that intra-articular osteoid osteoma of the talus should be considered in young patients with persistent atraumatic ankle pain and diffuse marrow edema when the clinical course becomes discordant with avascular necrosis.