Multicentric osteoid osteoma with a nidus located in the epiphysis.

We present a 13-year-old girl who was referred to our clinic with a 5-month history of right leg pain relieved by salicylates. Initial CT examination demonstrated a lesion in the posterior tibial cortex in keeping with an osteoid osteoma. This was resected and the diagnosis confirmed by histology. However, her pain recurred 2 weeks after the operation and further imaging identified a further nidus in the epiphysis. We present the imaging findings in this unique case of multicentric osteoid osteoma with one nidus located in the epiphysis.