Osteoclastoma distal femur LSBU

Description: ACR-code 451-3182 2 cases
Clinical presentation: 22 year old female with pain in the left knee. There is a destructive bone lesion in the distal metaphysis and lateral condyle of the left femur. It extends to the joint surface and has eroded the cortex and extends laterally with a soft tissue bulge beyond the remaining intermittent density of the original bone margin. The diverging thick lateral cortical densities, just above the knee joint, resemble more projection of two loculi, rather than any lamellar elevation of the periosteum. The lateral view shows no indication of an extra-axial invasive soft-tissue mass. The endosteal margin of the lesion is fairly narrow, although the edge is not crisp. The abundant fat-planes show disuse muscle atrophy. Patchy porosis of the tibia and fibula is probably also disuse.
Clinical presentation: 32 year old man with gradual onset of pain in the left knee. The plain film images show an expanding cyst-like lesion in the lateral condyle of the left femur, extending to the joint suface on that side. It expands the bone and has a well defined endosteal margin with a narrow zone of transition between normal and abnormal bone. The lesion is multiloculate, best seen in the MRI images, and shows predominant water content with visible layering of fat and water.