Osteosarcoma - femur

Case contributed by Dr Mostafa El-Feky

Presentation

Right thigh swelling and pain. The patient was histopathologically diagnosed osteosarcoma since 6 months. Currently, came for a follow up scan after chemotherapy.

Patient Data

Age: 10 years
Gender: Female
CT

A large infiltrative bone mass lesion epicentered on the lower shaft of the right femur with moth-eaten pattern of destruction of the overlying cortex and speculated type of periosteal reaction as well as Codman triangle formation. It shows predominantly sclerotic nature of the lesion with heterogeneous new bone formation, extending to the nearby soft tissues.

MRI

An ill-defined infiltrative medullary lesion is noted involving the distal right femoral meta-diaphyseal region measuring about 7 x 9.5 x 17 cm in maximum dimensions. It expresses heterogeneous iso to hypo-intense signals on T1, mixed intermediate & hyperintense signals on T2 & T2 fat sat with constant hypointense areas corresponding to new bone formation.

Intra-lesional cystic areas with fluid-fluid levelling most appreciated on T2 & T2 fat sat W sequences. The lesion showed moderate heterogeneous post-contrast enhancement.

The lesion is associated with large soft tissue component circumferentially encasing the distal femoral shaft with infiltration of the vastus intermedius & to lesser extent vastus medialis muscles. Focal invasion of the distal femoral growth plate is also noted. Respected neuro-vascular bundle. The left thigh is unremarkable.     

Case Discussion

This case represents the classic appearance of osteosarcoma, intramedullary type. The case was histopathologically proved since 6 months and was treated with chemotherapy till this follow up scan. Osteosarcoma commonly occurs commonly at the metaphysis of the appendicular bones with the femur represents ~40% of its sites. Primary osteosarcoma occurs at a young age, typically 10-20 years. If a limb-salvage procedure is feasible, a course of multidrug chemotherapy precedes surgery to downstage the tumor, followed by wide resection of the bone and insertion of an endoprosthesis. 

 

Case courtesy of Dr Rim Bastawy, assistant lecturer, Alexandria University.

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Case information

rID: 64984
Published: 21st Dec 2018
Last edited: 25th Dec 2018
Inclusion in quiz mode: Included
Institution: Dar El Ashaa Center

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