An unusual destructive lesion of bone was first examined six months following trauma to the tibia; it was limited to the cortex of the bone, and showed no periosteal or medullary involvement. Histologically the cortical bone was replaced by fibrous tissue and giant cells. There was associated old and fresh hemorrhage, but there was no evidence of new-bone formation.
This lesion does not fall within any definitely known category of bone pathology. It is best considered as a benign lesion which represents an unusual reparative response on the part of the bone to injury.