Ewing sarcoma of the pelvis

Case contributed by Aravinda Perera
Diagnosis certain


Right sided hip pain and a limp. Pain worse at night.

Patient Data

Age: 7 years
Gender: Male

Ill-defined sclerosis at the superior lateral aspect of the right ilium with cortical irregularity and periosteal reaction. This region demonstrates a wide zone of transition consistent with an aggressive appearance.

No other convincing bony abnormality demonstrated. No fracture or dislocation identified. The partially visualized bowel gas pattern is normal.

Conclusion: Indeterminate lesion involving the right ilium requiring MRI for further assessment.


Aggressive bony lesion involving the right ilium. The lesion is centered within the lateral aspect of the right iliac wing and extends down from iliac crest to the anterior inferior iliac spine. Apparent cortical destruction involving both deep and superficial cortices of the right iliac wing. Lamellated aggressive periosteal reaction with associated periosteal mass both deep and superficial to the right iliac wing. Adjacent soft tissue edema deep to iliacus and more extensively related to the superficial component involving gluteus medius muscle. The periosteal mass demonstrates heterogeneous contrast enhancement.

Mild confluent T2 hyperintensity and increased contrast enhancement extends beyond the limits of the discrete bone lesion to involve the entirety of the right ilium reaching lateral margin of right sacroiliac joint and superior margin of triradiate cartilage without involvement of the pubis or ischium.

No joint effusion. No regional lymphadenopathy demonstrated. Lower lumbar spine, sacrum and both femoral heads of normal appearance.

Imaging findings are concerning for primary bone neoplasm and suggestive of Ewing sarcoma.

Case Discussion

An open biopsy of the right iliac lesion was performed promptly following the findings on MRI. Histological analysis of the biopsied tissue confirmed a diagnosis of Ewing sarcoma.

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