The lesion shows iso- to hypo signal intensity (SI) to muscle on T1WI,
heterogeneous hyper SI on T2WI and heterogeneous enhancement. There are multifoci
of dark signal intensity on all sequences in the mass, representing osteoid tumor matrix
formation. Codman triangle interrupted periosteal reaction is detected at
superoposterior aspect. No internal cystic lesion or hemorrhage is seen. There is no
pathologic fracture.
The included right femur, bilateral patella and fibula show normal marrow SI
without cortical destruction. No intramedullary skip lesion is seen. Both hip joints and
right knee joint appear unremarkable.
There is a lymph node at popliteal area, measured about 0.7 cm in short axis
dimension.
IMPRESSION
- A 6.7x5.7x5.6 cm intramedullary infiltrative lesion with internal osteoid tumor matrix
and Codman triangle interrupted periosteal reaction, extending from left distal femoral
metaphysis down to lateral femoral condyle, with lateral cortex destruction and
associated soft tissue mass, the lowest border located about 1.5 cm above the knee
joint line with intra-articular component in the lateral recess of suprapatellar pouch and
pressure effect to lateral patellar retinacula, vastus intermedius and vastus lateralis.
Conventional osteosarcoma is considered.
- Edema of anterior portion of short head biceps femoris muscle, the vastus
intermedius and vastus lateralis muscles. No intramedullary skip lesion.
- Intact neurovascular bundles.
- A lymph node at popliteal area, measured about 0.7 cm in short axis dimensionคำศัพท์ทางการแพทย์