대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Askin tumor (Extraskeletal Ewing’s sarcoma)

Radiologic Findings

Fig 1. A chest radiograph shows pleural based mass-like opacity in right lower lung zone and costophrenic angle blunting.
Fig 2. Non-contrast axial CT scan with mediastinal window setting shows a lobulated mass abutting the pleura in right lower lobe and small amount of pleural effusion in the dependent portion.
Fig 3. After 2 weeks, the follow-up chest radiograph shows diffuse opacification and pleural effusion in the right hemithorax. A drainage catheter is also noted.
Fig 4-6. Follow-up contrast enhancement axial CT scans in 2 weeks show large amount of multi-loculated pleural effusion, diffuse pleural thickening and multifocal pleural masses in the right hemithorax.

Brief Review

Askin tumor is a rare malignant tumor of the thoracopulmonary region from the group of peripheral neuroectodermal tumors. It usually occurs in children, adolescents and young adults, but can develop at any age. In contradistinction to osseous Ewing sarcoma, Askin tumor is more commonly seen in female patients. Histological examination reveals the undifferentiated sarcomatous tissue of small round cells. Under immunohistochemical examination, the tumor is positive for several neural markers, such as NSE, CD99 and vimentin. The differential diagnosis includes neuroblastoma, lymphoma, small cell carcinoma, rhabdomyosarcoma, and desmoplastic small round cell tumor.
At radiography, a large chest mass is a common finding and represents a combination of a pleural-based mass and pleural effusion. CT often demonstrates a large unilateral chest wall mass with heterogeneous attenuation, which is frequently associated with rib destruction and pleural effusion. Prominent vascular enhancement after intravenous contrast material administration is often demonstrated and reflects tumor hypervascularity. Tumors often have both intrathoracic and extrathoracic components with pleural, pericardial, diaphragmatic and vertebral or spinal extension. Pulmonary involvement can lead to lung collapse. Calcification is uncommon (10%). Ipsilateral hilar and mediastinal adenopathy and pneumothorax are other associated findings.

Please refer to

Case 250, Case 354,

References

[1] Benbrahim et al. Askin’s tumor: a case report and literature review World Journal of Surgical Onconcology 2013;11:10
[2] Karatziou C. et al. A case of extraskeletal Ewing sarcoma originating from the visceral pleura HIPPOKRATIA 2011;15(4):363
[3] Mark D. Murphey et al. Ewing Sarcoma Family of Tumors: Radiologic-Pathologic Correlation Radiographics 2013;22:803
[4] Mustapha L. et al. Rapidly fatal Askin’s tumor: a case report and literature review Pan African Medical Jounal 2014;18:104

Keywords

pleura, Primitive Neuroectodermal Tumor (PNET, Askin Tumor),