Epiphyseal extension of an aneurysmal bone cyst of the left distal femur in a 14-year-old girl. An anteroposterior radiograph of the left femur shows a well-defined, lytic, expansile metadiaphyseal lesion (black asterisk) with multiple internal septations causing cortical thinning. There is clear epiphyseal extension (white asterisk) of the lesion across the physis (arrow)