- Apart from focal collagenisation (scarring often with haemosiderin) there no matrix formation; i.e the tumor cells do not produce bone or cartilage tissue. Reactive bone formation may occur, for instance.
32-year-old female, pain in the knee area. The X-ray shows round osteolysis in the proximal tibial epiphysis with discrete marginal sclerosis. The specimen is material from a curettage.
- cell-dense tumour tissue with relatively homogenous mixture of 2 cell types:
1. multinucleated giant cells
2. middle-sized, polygonal to spindle shaped cells with no nucleus