Osteosarcoma of humerus

Case contributed by Dr Karim Hussein

Presentation

10 year old female presented with shoulder pain after playing basketball.

Patient Data

Age: 10
Gender: Female
X-ray

Permeative lytic lesion over the left proximal diametaphyseal region. With loss of the cortex laterally.

Appearances are consistent for an aggressive bony lesion and osteomyelitis may also have a similar appearance

CT

Destructive lytic lesion in the proximal humerus with.

There is destruction of the lateral cortex of the upper humerus with a soft tissue component which expands mildly out of the lateral side of the lesion.

Appearances in keeping with a malignant bone lesion.

Osteosarcoma, Ewing's sarcoma, metastasis or lymphoma could be considered in the differential diagnosis. 

MRI

There is considerable bony destruction involving the lateral and posterolateral cortex through the diametaphyseal region with elevation of the periosteum and minor extension beyond the periosteum.

Post-contrast T1 images demonstrate enhancement which corresponds almost exactly with the area of high T2 signal. Through the central portion of the lesion there is an irregular large area of non enhancement which corresponds with heterogeneous T2 signal. This likely reflects a central necrotic portion of the lesion.

The extensive periosteal reaction and cortical changes at the lateral and posterolateral aspect of proximal diametaphyseal region is predominantly lamellated rather than sunburst in type.

This favours malignancy over infection given there is no extension of oedema beyond the areas of enhancement.

Pathology

Histology consistent with osteosarcoma.

Case Discussion

On plain X-ray and CT radiological appearance could represent aggressive bony lesion or osteomyelitis. However, clinical presentation of pain following minimal trauma and no infective symptoms made osteomyelitis unlikely.

On MRI osteomyelitis is excluded as there is no extension of oedema past the areas of enhancing lesion.

The laminated appearance of the periosteal reaction is usually more commonly seen in Ewing's sarcoma with a sunburst appearance more commonly seen in Osteosarcoma. However, both patterns can be seen in osteosarcoma, Ewing's Sarcoma and osteoblastic metastases. 

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Case information

rID: 56021
Published: 15th Oct 2017
Last edited: 15th Oct 2017
Inclusion in quiz mode: Excluded

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