Clinical presentation:
16 year old girl with painful swollen right shoulder.

There is a reduced bone density in the proximal metaphysis and the fusing epiphysis of the right humerus. The endosteal margin of the lesion in the diaphysis is ill-defined with a wide zone of transition between normal and abnormal bone. There is elevation of the periosteum that also marks the lower extent of the lesion. The lamellar periosteal newbone shows the presence of Codman's triangles on both sides of the upper section of the diaphysis. Soft tissue density with additional contained ossific density, separate from the expected density of the deltoid also indicates extra-axial extension. The epiphyseal line is just visible.

In this later view, the lamellar newbone has extended over the upper diaphysis of the right humerus and has produced increased bone density. The increased extra-axial soft-tissue mass is marked by increased strands and patches of newbone. Bone and cortical destruction can be seen just below the lateral margin of the epiphysis.

The heart size is normal. There is a relative reduction in the volume of the right lung with lower zone densities, including poor definition of the right cardio-phrenic angle. There is a visible nodule in the right third anterior rib interspace; less well-defined soft-tissue densities are projected lateral to this. Further densities are projected over the right 2nd and 3rd ribs in the right axilla. A nodule may be present, where the left 2nd rib crosses the posterior margin of the left 6th rib. The suggestion of a left para-spinal soft tissue density is probably due to the projection of slightly dilated left lower lobe bronchi.