Despite its somewhat atypical location in the fibula, the radiographic appearance and demographic are classic for Langerhans cell histiocytosis.

There are multiple features which connote that this is an aggressive lesion:

• wide zone of transition
• lamellated pattern of periostitis - suggests that physiologic process of bone healing cannot "keep up" with the tissue destruction encited by the lesion
• associated soft tissue swelling

In the absence of signs or symptoms of infection to suggest osteomyelitis, the differential for an aggressive-appearing lesion in a child includes metastasis (e.g. neuroblastoma), blue round cell tumor, and primary osseous lymphoma.