Presentation
Painless swelling of the posterior aspect of the right thigh.
Patient Data
There is an ovoid soft tissue mass of the posterior aspect of the right mid-thigh, of intramuscular location within the adductor magnus muscle measuring 67 x 58 x 46 mm. It elicits an iso-to high signal to the muscles on T1, heterogeneous high signal on T2/STIR with areas of fluid-fluid levels and thick, irregular septae of low signal. The postcontrast sequences show a peripheral irregular enhancement as well as the septae. No apparent extension to the adjacent muscles. Normal appearance of the femoral vessels and sciatic nerve.
Case Discussion
The MRI features are suggestive of a malignant tumor of intramuscular location within the adductor magnus muscle, pathologically proven as a synovial sarcoma biphasic subtype.