giant cell tumor

osteoclastoma, GCT

any age, typically 20-35
site:
- metaphysis into epiphysis
- 50% at knee (distal femur, proximal tibia)
- long bones, patella, spine
eccentric, expansile
+/- "soap bubble" appearance
tx: curette, fill with methacrylate
10% recur, a few are premalignant or malignant
cannot determine malignancy by XR