Case 8

A previously healthy 6-year-old female child presented with a progressive swelling in the left shoulder region that had been gradually increasing in size over the past two months. Initially, the swelling was painless but had recently become tender to touch. There was no history of trauma or injury to the shoulder, and the patient did not report fever, weight loss, night sweats, or other systemic symptoms. On local examination, a visible swelling was noted over the left shoulder deltoid region, measuring approximately 5 cm in diameter. The swelling was firm, tender on palpation, and showed no overlying skin changes or warmth. The range of motion in the left shoulder was limited due to pain and swelling. No lymphadenopathy or other abnormalities were detected on the rest of the physical examination.

IMAGING FINDINGS:

X-ray 

Large expansile mass involving the proximal humeral metaphysis.

MRI left shoulder with Contrast

Significant extra-osseous component extending laterally beneath the deltoid and medially into the axilla. The mass appeared isointense to muscle on T1-weighted images, heterogeneously hyperintense on T2-weighted images, and demonstrated extensive contrast enhancement.

Bone scan

Increased radiotracer uptake in the left proximal humerus, consistent with the site of the lesion.

Biopsy & Staging Workup 

A biopsy of the lesion showed small round blue cells with positive staining for CD99 and FLI-1, confirming the diagnosis of Ewing sarcoma. Staging workup, including CT chest, bone scan, and bone marrow aspiration and biopsy, showed no evidence of pulmonary metastasis, distant bony metastasis, or bone marrow involvement.

Management

The patient was managed with a multidisciplinary approach involving a pediatric oncologist, orthopedic surgeon, and radiation oncologist. Chemotherapy with the VDC/IE regimen was administered in cycles with careful monitoring. Following tumor size reduction, surgical resection with wide margins was performed, and the proximal humerus was reconstructed with a prosthetic implant. Post-operatively, adjuvant radiation therapy was given to eliminate residual microscopic disease.

IMAGING

X-RAY LEFT HUMERUS

MRI LEFT SHOULDER WITH CONTRAST

Key Imaging Findings in Ewing Sarcoma

X-ray:

• Classic Appearance:

  • Permeative lytic lesion

  • Periosteal reaction:

    • Onion-skin: Layered/lamellated periosteal lifting

    • Codman’s Triangle: Triangular periosteal elevation, indicating aggressiveness

  • Soft tissue mass

• Location:

  • Primarily diaphysis of long bones, but also seen in the metaphysis and flat bones (pelvis, ribs, spine)

• Aggressive Features:

  • Poorly defined margins with a moth-eaten/permeative pattern

  • Cortical destruction with soft tissue extension

MRI:

• Soft tissue mass with T1 hypointensity, T2 hyperintensity, and heterogeneous contrast enhancement

• Neurovascular involvement—crucial for surgical planning

CT scan:

• Cortical destruction, aggressive periosteal reaction, soft tissue extension, and possible lung metastases

Bone Scan/PET-CT:

• Increased uptake indicates bone involvement and distant metastases