This case represents the classic appearance of osteosarcoma, intramedullary type. The case was histopathologically proved since 6 months and was treated with chemotherapy till this follow up scan. Osteosarcoma commonly occurs commonly at the metaphysis of the appendicular bones with the femur represents ~40% of its sites. Primary osteosarcoma occurs at a young age, typically 10-20 years. If a limb-salvage procedure is feasible, a course of multidrug chemotherapy precedes surgery to downstage the tumor, followed by wide resection of the bone and insertion of an endoprosthesis. 

Case courtesy of Dr Rim Bastawy, assistant lecturer, Alexandria University.