A six-year-old girl was brought with a painless swelling over the posterior aspect of the right knee joint that had been present since birth. There was restriction of movement at the knee joint.
Photograph of the swelling on the patient's leg.
Frontal and lateral radiographs of the right knee joint show a large well-defined exophytic bony outgrowth arising from the proximal metaphyseal end of the right fibula. The growth demonstrates continuity of cortical components with the parent bone. There is also a bony outgrowth at the distal meta-diaphysis of the right femur and the proximal meta-diaphysis of the right tibia.