Presentation
Atraumatic leg pain.
Patient Data
There is a lucent lesion located centrally within the proximal tibial diaphysis. It demonstrates a relatively narrow but indistinct zone of transition. Periosteal reaction is seen involving the medial aspect of the tibia.
The cylindrical lesion demonstrates intrinsic low T1 and high T2 signal. It extends through the anteromedial tibial cortex with destruction of the bone. Periosteal elevation is also seen anteromedially. There is diffuse contrast enhancement and enhancement of a soft tissue component.
Low signal within the posterior and medial cortex suggests an associated stress fracture.
No skip lesion is seen.
Case Discussion
Ewing sarcoma is an aggressive bone tumor of childhood. It is most commonly intramedullary, involving the metadiaphysis. The femur is the most common location.
Onion-skin periosteal reaction is typically described.