Figure 1.

(A and B) Plain radiograph of the left femur shows an expansile multilobulated lytic lesion with ‘soap-bubble’ appearance at the diaphysis of the left femur. Cortical thinning and endosteal scalloping (black arrow) are apparent in most parts of the lesion. Some areas of the cortex are imperceptible and interrupted (white arrowhead). There are lobulated soft tissue swellings causing cortical erosion of the posterior distal femur (asterisk). Secondary osteoarthritis of the left knee is apparent.