2023 Friday Quiz 8 Answer | Figure 1

CincyKidsRad

Cincinnati Children's Radiology

2023 Friday Quiz 8 Answer

Coronal (image 1) and axial (image 2) T2 weighted MRI show a Ewing sarcoma (arrow) of the left iliac bone. The mass has a large soft tissue component. Ewing sarcoma is the most common pelvic sarcoma in children. Compared to osteosarcoma, Ewing sarcoma is more likely to affect flat bones and have an associated soft tissue mass.

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Coronal (image 1) and axial (image 2 and 3) CT of the kidneys shows a poorly defined mass (arrow) in the upper pole of the right kidney. The mass was ultimately diagnosed as an extraosseous Ewing sarcoma. Extraosseous Ewing sarcoma is a rare variant of Ewing sarcoma typically occurring in the paravertebral spaces, lower extremities, head and neck, and pelvis. Renal involvement is uncommon. Patients with extraosseous Ewing sarcoma are typically older than those with skeletal tumors.

Axial T2-weighted MRI (image 1) and coronal T1-weighted postcontrast MRI (image 2) performed in a child show a solid, non-enhancing mass (arrow) arising within the midportion of the left kidney. The most common renal malignancy in a child is Wilms tumor followed by renal cell carcinoma. In this instance, the tumor was confirmed to represent a soft tissue Ewing sarcoma. Extra-skeletal Ewing's sarcoma most commonly arises from the paravertebral spaces, lower extremities, head and neck region, or the pelvis. Renal Ewing sarcoma is incredibly rare.

Sagittal (image 1) and axial (image 2) T1-weighted postcontrast MR images obtained in an adolescent with metastatic Ewing sarcoma show a skull metastasis affecting both the inner and outer table of the skull. Anterior and posterior projection from whole-body technetium 99m-MDP bone scan (image 3) show metastases affecting the skull, vertebral bodies, pelvis, humeri, ribs, and sacrum. Ewing's sarcoma is the second most common primary bone malignancy in children after osteosarcoma. The median age at time of diagnosis is 15 years. When metastases occur, they most commonly affect the lungs and bones.

AP radiograph of the pelvis (image 1) and zoomed-in portion of the radiograph (image 2) show an aggressive Ewing sarcoma affecting the right superior pubic ramus. The tumor is causing the bone to be sclerotic with spiculated periosteal new bone formation. Axial T1-weighted postcontrast (image 3) and T2 (image 4) MRI show a large soft tissue component (arrow). Ewing sarcoma is the second most common primary bone malignancy of childhood. They most commonly occur in patients between 10 to 20 years of age. While the tumor most commonly occurs in the femur, approximately 1 and 5 originate in the pelvis.