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Age / Sex : 52 / F
Chief complaint: Right forearm swelling and pain, trauma history (+)
What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case. (Please submit only one answer)
Courtesy: Yoonah Song, Hanyang University Hospital
Diagnosis: Ewing sarcoma/Primitive neuroectodermal tumor (ES/PNET)
Discussion
Findings:
X-ray: Permeative osteolysis with periosteal reaction showed in mid- to proximal radius. It also showed diffuse skin and subcutaneous fat edema at postero-lateral aspect of forearm.
MRI: Diffuse bone marrow signal change was showed at intramedullary and subcortical portion (mid- to proximal radius) with periosteal reaction. The lesion also had bulky extraosseous component and markedly enhancement without definite evidence of diffusion restriction.
Differential Diagnosis: Osteomyelitis
Diagnosis: Ewing sarcoma/Primitive neuroectodermal tumor (ES/PNET)
Discussion:
Ewing sarcoma of bone represents the second most common primary malignant tumor of bone in children and adolescents. Ewing sarcoma is most frequent in the first 3 decades of life, with 95% of cases reported between the ages of 4 and 25 years. There is a slight male predilection. Long tubular bone involvement is more common proximally than distally. Osseous lesions originate in the central medullary canal, with early involvement of the soft tissues in 80%-100% of cases. Soft-tissue masses are usually large and circumferential about the involved bone; they may exceed the intraosseous component in size in 2%-15% of cases. The communication between the medullary canal and soft-tissue components may be through focal cortical destruction. Periosteal elevation is common.
Histologic sections show crowded sheets of small round blue cells or lobules of such cells divided by a small amount of fibrous stroma. The nuclei and round with indentations of the nuclear membrane and small nucleoli. The cells may also form Homer-Wright rosettes, in which they are arranged around a central fibrous core, or pseudorosettes, with arrangement around a central blood vessel. Historically, greater than 20% of tumor tissue showing this rosette formation was used as a criterion for diagnosis of PNET, although this extent is rare.
References:
Mark D. Murphey et al. Ewing Sarcoma Family of Tumors: Radiologic-Pathologic Correlation Radiographics 2013; 33:803-831
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