CASE 67
By: Dr. Amna Kashgari MD,SSC-Rad
HISTORY: A 9-year-old boy with left shoulder pain with restriction of movement.
What are your findings?
What is your differential diagnosis?
What is your most likely diagnosis?
FINDINGS:
Frontal radiograph of the shoulder (A) demonstrates aggressive lytic lesion in the scapula with wide zone of transition. Soft tissue component noted adjacent to the lesion.
Axial fat suppressed T2-weighted MR image (B) reveals infiltrative bone lesion with a large associated soft-tissue mass. The lesion shows heterogonous intermediate signal intensity with neurovascular bundle encasement. Coronal T1-weighted image with contrast (C) demonstrates heterogeneous enhancement of the lesion.
DIFFERENTIAL DIAGNOSIS:
Ewing sarcoma.
Metastasis.
Lymphoma.
Osteomyelitis.
DIAGNOSIS:
Ewing sarcoma.
PEARLS AND DISSCUSSION:
Ewing sarcoma of bone is the second most common primary malignant tumor of bone in children and adolescents, after osteosarcoma.
Age group between 4-25 years (peak prevalence between 10-15 years).
Male to female ration is 1.5:1.
The most common affected sites are the femur followed by ilium (12–13%), extremities, ribs and sacrum. Other bones like scapula are less frequently involved.
Clinical presentation:
Presentation is non-specific with local pain, palpable soft tissue mass or pathological fractures. Constitutional symptoms may present.
Radiological features:
Plain radiograph:
Aggressive bone lesion with a moth-eaten to permeative pattern, wide zone of transition and cortical destruction periosteal reaction is usually aggressive in appearance either lamellated (onionskin) or spiculated (sunburst or hair-on-end). Associated soft tissue component is common.
Less common appearance of Ewing sarcoma is sclerosis with cortical thickening.
MRI findings:
It reveals marrow replacement and cortical destruction with an associated soft-tissue mass. The soft-tissue mass is commonly circumferential but asymmetric.
T1-weighted images the lesion shows homogeneous and intermediate signal intensity.
T2-weighted images it is typically homogeneous and low to intermediate in signal intensity.
(Due to high degree of cellularity in Ewing sarcoma small blue round cell tumour). Heterogeneity and high signal intensity are more common in larger lesions and represent hemorrhage or necrosis.
Post contrast images show heterogeneous enhancement.
Differential diagnosis of aggressive bone lesion in pediatric:
Metastasis.
Osteomyelitis.
Haematogenous malignancy.
Osteosarcoma.
FURTHER READING:
Mark D. Murphey, Lien T. Senchak et al. Ewing Sarcoma Family of Tumors: Radiologic-Pathologic Correlation. RadioGraphics 2013; 33:803–831
Lane F Donnelly. Fundamental of pediatric radiology. ISBN-13: 978-0721690612
Johan G Blickman, Bruce R Parker, Patrick D Barnes. Pediatric Radiology: The Requisites, 3e. ISBN-10: 0323031250
