Malignant tenosynovial giant cell tumor following resection, evaluate for local recurrence There are extensive surgical changes of the knee resulting from patellar resection and soft tissue reconstruction. The medial head of the gastrocnemius has been transposed as a flap along the anteromedial aspect of the proximal tibia. This graft is contiguous with a reconstructed extensor mechanism which can be traced to its insertion on the tibial tuberosity distally and the quadriceps tendon proximally. The reconstructed tendon appears thickened with heterogeneous increased signal on short TE sequences, which may represent degeneration or tendinosis; although we cannot exclude partial-thickness tearing, there is no abnormal fluid signal on STIR sequences to suggest full-thickness disruption. There is mild thickening and enhancement of the skin of the knee. Additionally, there is bandlike enhancing tissue traversing the subcutaneous fat of the knee which likely represents scarring. Heterogeneous enhancement of the reconstructed extensor tendon is noted with additional amorphous enhancement anterior to the biceps femoris muscle. Although it is impossible to exclude small tumoral deposits, we suspect these changes are also related to scarring and there is no dominant focus of nodular enhancement to confirm recurrence.Metallic susceptibility artifact is seen along the anterior tibial tuberosity. There is a moderate-sized joint effusion with thickening and enhancement of the synovium indicating synovitis. The underlying bone marrow is of normal signal. There is diffuse edema of the subcutaneous fat.Although not tailored for the evaluation of the internal structures of the knee, the menisci and collateral ligaments appear intact. A small full-thickness cartilage defect is noted of the femoral trochlea inferiorly.
Extensive surgical changes due to soft tissue reconstruction of the knee with amorphous enhancing soft tissue further detailed above. Although it is impossible to exclude small tumoral deposits, it is suspected that this enhancement reflects scarring as there is no dominant nodular focus of enhancement to confirm recurrence.