72-year-old female with a right thigh mass status post radiation therapy. There is a large mass within the anterior compartment of the right thigh measuring 14.5 x 12.3 x 23.6 cm (TR x AP x CC) which results in medial displacement of the rectus femoris and vastus medialis muscles (41; series 601). The mass also displaces the femoral vessels medially, but does not definitively contact the vessels themselves. The mass is largely isointense to muscle with a few hyperintense foci likely representing subacute blood products. The mass demonstrates predominantly fluid signal intensity on T2-weighted images with low signal intensity septations. The majority of the mass does not enhance following administration of contrast although there is a peripheral rind of enhancement. There is also edema type signal intensity and enhancement of the vastus lateralis muscle belly posteriorly and distally which may reflect denervation, although we cannot entirely exclude tumor extension. The signal abnormality and enhancement within the vastus lateralis muscle contacts the femur, as does enhancing tissue arising from the posteromedial aspect of the mass, but we see no signal abnormality within the cortex or medullary cavity of the femur itself to suggest tumor invasion. There is mild edema and enhancement within the anterior musculature of the hip. There is a small knee joint effusion with enhancement suggestive of a mild synovitis which is nonspecific.
Large soft tissue mass as described above.