Clinical Presentation

The patient is a 15-year-old girl with pain and swelling of the left thigh for 4 months.

Further Work-up

(A) Radiograph of the left femur display an aggressive-appearing segment of a lamellar (white arrow) and spiculated (black arrow) periosteal reaction with a Codman triangle (c) along the distal femoral diametaphysis. An associated soft-tissue mass (M