Presentation
Painful swelling around the left knee of 2 weeks duration
Patient Data
Distal femoral metaphyseal eccenteric aggressive marrow lesion that displays low signal in T1 with small high signal foci likely hemorrhage and heterogenous signal in T2, high signal in STIR and avid enhancement in post contrast study. There is associated cortical destruction, extraosseous soft tissue extension, periosteal infiltration and marrow edema and microinvasion of the adjacent area of distal femur.
Diagnosis: Osteogenic sarcoma (histologically proven)
Case Discussion
Osteosarcoma has many subtypes however the conventional type is the one in this case. It can occur as primary on healthy bone or secondary to Paget disease or post infarction/irradiation. Osteosarcoma can metastasize to other bones and lungs. Bone scan and CT chest are recommended for staging of this case.