Ossifying fibroma of the long bones. Radiological diagnosis, differential diagnosis and management implications.

We report a case of ossifying fibroma of the long bones (OFLB). This lesion, occurring mainly during the first decade of life, typically affects the tibial diaphysis and clinically presents as a painless bony enlargement. Radiographic features include an osteolytic cortical expansion, containing diffuse calcifications, and separated from the medullary by a thick cortical rim. CT appears to be the examination of choice to define these signs and permits differentiation from monostotic fibrous dysplasia and from adamantinoma (by demonstrating the presence or absence of diffuse high attenuation values). The importance of making the differential diagnosis is stressed, as prognosis and management of OFLB, fibrous dysplasia and adamantinoma may vary considerably.