Clinicopathologic study on seven cases of osteofibrous dysplasia was performed. The mean age of the patients at the time of first examination was 6.4 years and all of them had an intracortical, eccentric lesion in the anterior aspect of the shaft of the tibia. Six of them underwent an excision or an en-block resection and five of the six patients recurred, being accompanied by pathologic fractures and/or pseudarthrosis, the results of operation were not satisfactory. Meanwhile, one case who was treated conservatively with a PTB brace showed relatively satisfactory results. The patients under the age of ten years might not have to be operated.
Although the histologic finding of osteoid rimmed by osteoblasts is typical in this condition, we had four cases showing this finding which could not be diagnosed clinically as osteofibrous dysplasia. The histologic feature of osteoblastic rimming is, therefore, not necessarily characteristic to osteofibrous dysplasia. In osteofibrous dysplasia the number of osteoclasts around osteoid is larger and collagen fibers in the stroma are less abundant than those in fibrous dysplasia, which may be related to the aggressive potentiality of the disease.
