Osteosarcoma: femur

Case contributed by Dr Sinéad Culleton


Left leg pain.

Patient Data

Age: 15 years
Gender: Male

Cortical thickening in the medial left femoral diaphysis. Aggressive sunburst periosteal reaction.


Large soft tissue mass in the proximal femoral diaphysis with associated bone oedema on STIR. No skip lesions identified.

Case Discussion

Osteosarcoma is the commonest primary bone tumour in children and teenagers 1. Osteosarcomas produce a bony matrix. It can however present as a lytic or mixed lytic-sclerotic lesion. There is associated irregular cortical destruction and an aggressive periosteal reaction.

 There are a number of subtypes, some of which may resemble benign entities. A paraosteal osteosarcoma can resemble an osteochondroma (the commonest benign bone tumour) and myositis ossificans. An osteochondroma will show a juxtacortical bone lesion in contact with the underlying medullary canal, an osteosarcoma will not show this corticomedullary continuity.

 In myositis ossificans the lesion will ossify from the periphery towards the centre but in an osteosarcoma the lesion ossifies from the centre out towards the periphery 1.

A telangiectatic osteosarcoma may resemble an aneurysmal bone cyst. The fluid levels in a telangiectatic osteosarcoma are usually blood. It will have an aggressive growth pattern, osteoid matrix mineralisation and nodular septal thickening, features not identified in an ABC 1.




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Case information

rID: 45223
Published: 18th May 2016
Last edited: 19th May 2016
Inclusion in quiz mode: Excluded

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