Symmetrical fibro-osseous dysplasia of rib--post-traumatic dysplasia?

We describe two patients with a distinctive histological condition which clinically and radiologically mimics fibrous dysplasia of the rib. Both patients presented with chronic pain confined to one rib. In each case their radiographs showed a solitary, fusiform expansion of a rib with variable calcification. Histologically the lesions were characterized by a central core of xanthomatous macrophages surrounded by cancellous bone that showed symmetrical and progressive maturation centrifugally towards the cortex, a pattern which distinguishes these lesions from the irregular pattern of fibrous dysplasia.