Figure 3.

(a) Ill-defined mixed lytic sclerotic lesion in the mid to distal femoral shaft (arrowhead) with adjacent irregular periosteal reaction (arrows). (b) T1-weighted MR image of the same patient showing extensive T1 hypointense marrow changes in the femoral shaft, subsequently found to represent PBL. (c) Knee radiograph of another patient with PBL showing an ill-defined lytic sclerotic lesion (arrow) in the metaphysis of the distal femur. (d) CT scan of the same patient in the bone window shows central sclerotic sequestrum (arrow) with surrounding patchy sclerosis (arrowhead).