Large well-defined heterogeneous soft tissue mass lesion occupying most of the left vastus intermedius muscle. It measures about 17 x 11 x 10 cm and is isointense to muscles on T1 and mildly hyperintense on T2-weighted images. Mild diffusion restriction is noted on diffusion weighted images. Post-contrast images show extensive enhancement of the solid component and multiple non-enhancing necrotic areas. Extensive high T2 signal (edema or infiltration?) is noted in the remaining portion of the muscle. Intact vastus lateralis, vastus medialis as well as rectus femoris muscle. No signs of invasion of the underlying femur. The neurovascular bundle (in the abductor canal) is intact.