Presentation
Right thigh swelling and pain.
Patient Data
Skeletally immature patient.
Permeative destructive lesion of the distal femoral diaphysis. The lesion has a wide zone of transition with periosteal reaction and a likely soft tissue component.
Extensive heterogeneous intramedullary marrow signal affecting the distal two thirds of the right femoral shaft. The cortex is expanded and breached in several places.
Large associated soft tissue extension 8 cm in transverse dimensions and 29 cm in longitudinal dimensions. The abnormality reaches to within 2.5 cm of the greater trochanter. Small 1 cm focal high signal just below the intertrochanteric line, maybe a skip lesion.
The hip joint is not involved.
The soft tissue component abuts the neurovascular bundle in the thigh at its posterior aspect, but no definite encasement.
Case Discussion
The findings are consistent with an extensive malignant mass in the right femur, likely to be an osteosarcoma, which was subsequently confirmed at surgical biopsy.