The specimen includes the lower end of the femur together with the upper end of the tibia. In the
lateral condyle of the femur there is a rather poorly-defined greyish-white area perhaps better seen
from the back. The tumour extends to the articular cartilage but does not appear to be beyond it
and there does not appear to be any extension beyond the periosteum.
This woman presented in her sixties with a history of a swollen painful left knee for some
18 months. This was treated initially as an osteoarthritis but further investigation showed the
presence of this tumour.