Name 3-5 radiographic features of the present lesion.
1. metaepiphyseal location 2. subchondral bone involvement 3. translucency 4. cortical expansion 5. well-defined, partly sclerotic margins 6. lobulated (geographic) contours 7. central ridges and grooves (pseudotrabeculae)
What is the differential diagnosis for this lesion?
Giant cell tumour of bone (GCT), aneurysmal bone cyst (ABC), and chondromyxoid fibroma. Chondroblastoma and non-ossifying fibroma are both more usually found in younger patients.
What additional imaging studies are appropriate to narrow down the differential diagnosis and plan operative treatment?
MRI and CT
Expansile lesion of the proximal tibia with sharp zones of transition and expansion. It reaches the articular surface without breach of the cortex here or elsewhere. No matrix calcification or soft tissue component.