A well-defined eccentric, multi-septated radiolucent lesion with a narrow zone of transition and sclerotic margins is noted in the left distal femoral metaphysis. Mild endosteal scalloping is noted. No internal chondroid/ossific matrix, periosteal reaction, obvious fracture, or associated soft tissue abnormality is appreciable. A few possible differentials include ABC, fibrous dysplasia, or GCT.