Can osteoid osteoma become osteoblastoma? A case report.

A case of osteoid osteoma of the spine that recurred as an osteoblastoma 16 years after surgery is reported. Consequently, the authors suggest that osteoid osteoma and osteoblastoma originate from the same cellular element and are of the same nature. The only differences are their size and the reaction of the bone at the site of the lesion, which gives controversial clinical pictures and roentgenologic appearances, simulating two unrelated tumors.