To define the natural history and treatment of osteofibrous dysplasia, we compared the clinical courses of two groups: one group with a surgical treatment and the other group with a conservative treatment.

Seven cases (4 male, 3 female) were followed for more than two years (average f/u: 7 years 2 months). Four cases conservatively and three cases operatively by curettage and bone graft. Were treated the clinical and radiological findings of the two groups were compared.

Two of three cases that received surgical treatment had been diagnosed with lesion recurrence by radiography, which showed expansion of the cortical shell, resorption of grafted bone, and reactive bone formation. One other case exhibited shrinkage and confinement of the lesion to the anterior cortex. Two cases, which were treated conservatively, showed shrinkage of the lesion and an other two cases showed no change in the size in radiogram.

Asymmetrical intra-cortical osteolytic lesion of the tibia in children should be suspected as osteofibrous dysplasia and carefully observed until skeletal maturity, unless the structural integrity is seriously endangered.