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General sarcoma

 

Osteogenic sarcoma

Rhabdomyosarcoma

Non-RMS

 

 

Ewing Sarcoma

 

 

MR scan

 

In Ewing sarcoma (ES) magnetic Resonance (MR) imaging is the most effective technique for showing intramedullary and soft tissue extent of disease:

 

 

MR

Role

Shows:

  • Extent of bone marrow involvement and soft tissue invasion/involvement
  • Relationship to surrounding normal structures such as neurovascular bundle
  • Skip metastases (bone mets involving marrow at distant site from primary tumor in the same bone)

 

Appearance
  • T1 images:
            tumor = intermediate signal, similar to muscle
  • T2 images:
            tumor = heterogeneous, predominately high signal
  • STIR sequence water is bright - as in a T2 sequence, but there is also inherent fat suppression so pathology that usually contains water (as in ES) is easily visible

 

Limitations
  • MR findings are non-specific and do not aid in the differential diagnosis
  • Pattern of bone destruction better shown on plain film and CT
  • May be difficult to distinguish tumor from peri-tumoural edema

 

 

 

The coronal MR image below is a STIR sequence and shows a large soft tissue mass (A) associated with ES of the femur.  This is the same tumor shown in plain films .

 

The axial MR image (T2 sequence with added fat suppression) below shows the same soft tissue mass associated with ES (A) arising from the femur.

 

The MR below shows a soft tissue mass arising from the head of the clavicle (#1) in a patient with ES.

MR below shows ES arising from a vertebral body of the thoracic spine - associated with a soft tissue mass invading into spinal canal (#2) and causing spinal cord  compression.

 

Below are axial and coronal MR scans of ES arising from acetabulum with associated soft tissue mass (#s 3 and 4).

Below is an axial T2-weighted MR image showing increased signal within the right side of S1 and the large intraspinal soft tissue mass which extends through the left S1 neural foramen. This is a sacral ES and #5 points to the epicenter of the tumor,

 

 

 

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