Case report of intra-articular synovial sarcoma in the hip joint

Fig. 1. AP view of the pelvis showing permeation and erosion of the superior lateral aspect of the right femoral head and neck, associated with soft tissue swelling. Right ward tilting of the pelvis.

Fig. 2. Multiple series of coronal T2 fat-saturated, axial T1, T2 fat-saturated and axial, sagittal and coronal T1 post-contrast images showing a heterogeneous soft tissue mass involving the right proximal femur and causing erosion of the femoral head and neck. The mass originated from the hip joint, extended inferomedially and displaced the obturator internus and adductor muscles (a), and it was measured to be approximately 7 × 4 × 6 cm. Reactive soft tissue effusion was observed. The mass demonstrates isointense signals on the T1 images (b) and moderately high signal intensity on the T2 sequence images (c), with heterogeneous avid enhancement in the post-gadolinium images (d, e and f). Multiple necrotic foci were noted.

Fig. 3. Monotonous atypical spindle cells in a fascicular pattern with focal staghorn-like blood vessels. (H&E: 200X).