What is the diagnosis associated with layers of ossified periosteum resembling onion skin?

The diagnosis associated with layers of ossified periosteum resembling onion skin is Ewing sarcoma. This tumor is primarily seen in children and young adults and is characterized by a distinct periosteal reaction that manifests as "onion skin" or "onion skinning." This radiographic appearance results from the aggressive nature of the tumor, leading to the formation of multiple layers of new bone.

In Ewing sarcoma, the tumor typically arises in the long bones or the pelvis and can cause significant periosteal reaction due to its aggressive growth pattern. The appearance of the appearance of the periosteum and the surrounding tissues hence creates the "onion skin" effect.

In contrast, osteosarcoma, which typically produces a sunburst pattern or Codman’s triangle on imaging, does not manifest with the same periosteal layering as Ewing sarcoma. Chondrosarcoma primarily arises from cartilage, and although it can also cause bone changes, it does not have the same characteristic periosteal reaction. Fibrosarcoma, while it can also be aggressive, does not exhibit the distinct onion skinning pattern associated with Ewing sarcoma. Therefore, the correct association of the onion skin appearance with Ewing sarcoma makes it