Anteroposterior radiograph (A) of an aggressive giant cell tumour (GCT) in the distal radius of a 25-year-old male. Anteroposterior radiograph (B) of GCT of the distal femur in a 50-year-old male; note the thinning of the surrounding cortices. Anteroposterior radiograph (C) of an aggressive GCT of the proximal tibia in a 23-year-old female; the lesion has broken through the medial cortex.