Ewing’s sarcoma family tumor (ESFT) arising in the left femoral diaphysis of a 10-year old girl. (A) Plain radiograph demonstrates a permeative aggressive lytic bone lesion with soft tissue involvement. Codman triangles are present at the proximal aspect of the tumor; (B) post-contrast magnetic resonance imaging (MRI) reveals the extent of bone marrow and soft tissue involvement. The mid-diaphyseal location, the permeative nature of the tumor, and the presence of a soft tissue mass without frank cortical destruction, are all features of ESFT (Courtesy Dr. M. Beth McCarville, St. Jude Children’s Research Hospital, Memphis, Tennessee)