A 23-year-old man presented with severe pain at the right chest wall for more than a month. There was no history of trauma.
Plain films of the right rib cage (Fig. 1) showed a subtle triangular opacity projecting underneath the anterior aspect of the right diaphragm.
A subsequent CT examination of the chest (Fig. 2) confirmed an extrapleural, sharply lineated soft-tissue mass encasing the seventh right rib. There was an associated aggressive periosteal reaction (sunburst type) at the inner border of the seventh rib. There was heterogeneous enhancement of the lesion.
MR-imaging (Fig. 3) showed lesion extension into the muscles of the right chest wall. The lesion was of high signal on T2-weighted images and was iso-intense to muscle on the T1-WI. After intravenous administration of gadolinium contrast, there was a heterogeneous enhancement.
Based on the age of the patient and the imaging features, the lesion was very suspicious for Ewing’s sarcoma of the chest wall or Askin tumour. This was confirmed after histopathological examination of a biopsy of the lesion.
Ewing’s sarcoma is the second most common malignant bone tumour in young adults. Occasionally the lesion is located extra-skeletally, aka soft-tissue Ewing’s sarcoma or primitive neuroectodermal tumours (PNET). The peak incidence is the second decade of life. The male-to-female ratio is 1.5:1. The clinical presentation of Ewing’s sarcoma is nonspecific and includes pain and swelling at the affected site. Fever, weight loss, cough, anaemia and leukocytosis are less frequently seen. The most frequent locations are the pelvis, femur, tibia, humerus, fibula and ribs. [1, 2]
Askin tumours are soft-tissue Ewing’s sarcomas of the chest wall and are histologically similar to PNET and Ewing’s sarcomas of the bone. Cytogenetic and molecular evaluation techniques showed that all these tumours have the same genetic lineage, having a translocation between chromosomes 11 and 22. Most authors agree that Ewing’s sarcoma, PNET and Askin tumour are closely related and might even be identical lesions. Therefore, they are referred to as the Ewing sarcoma family of tumours. [2, 3]
Plain films show bone destruction, which is often associated with an aggressive periosteal reaction. Bone sclerosis may also be seen. A large associated soft-tissue mass is common. CT may be useful for detection of the lesion in complex anatomical areas, where there is a lot of superposition such as the skull base, pelvis and chest wall. [2, 4] MRI is superior to CT to assess bone marrow replacement and any associated soft-tissue component. The signal intensity is usually intermediate and inhomogeneous on T1-WI. On T2-WI the signal intensity varies from low (68%) to high (32%). Ewing’s sarcomas of the soft tissues are usually of high signal on T2-WI. There is always (heterogeneous) contrast enhancement. [1, 2]
Subtle cortical involvement can be seen as linear intermediate signal intensity channels permeating the cortex between the bone marrow and the soft-tissue component. This represents tumour extension along the Haversian canals and the neurovascular channels. In most soft-tissue Ewing’s sarcomas, there is usually no bone marrow extension but reactive periosteal reaction can be present if the lesion is adjacent to bone. Askin tumours -however- present often with rib destruction. [2]
The final diagnosis is made by histopathology. Treatment is multidisciplinary and involves (neo)adjuvant chemotherapy, surgical resection and radiation therapy. The prognosis of Askin tumour is poor compared to Ewing’s sarcoma at other sites. Two-year and 6-year survival rates of only 38% and 14% respectively have been reported. [2, 3]
Ewing’s sarcoma of the chest wall or Askin tumour.
1. X-ray (Chest, Anteroposterior and Lateral Views):
• A focal area of bone destruction is observed in the right chest wall rib, with possible cortical discontinuity.
• A soft tissue mass is visible in the region of the lesion, with unclear boundaries. The local rib contour appears blurred.
• There may be erosion or invasion of the adjacent rib.
2. CT Scan (Coronal and Axial Views):
• Clear evidence of local bone destruction in the right chest wall rib segment, with decreased rib density and tumor tissue extending into the soft tissue.
• The lesion shows an irregular soft tissue density, with heterogeneous enhancement after contrast administration.
• No obvious pulmonary parenchymal lesions are seen, but local pleura and musculature may be involved.
3. MRI (Axial and Sagittal Views):
• On T1WI, the lesion appears slightly low to isointense; on T2WI, it may appear isointense or hyperintense, typically with heterogeneous signals.
• Significant heterogeneous enhancement is observed after contrast, consistent with a characteristic malignant tumor appearance.
• The lesion extends along the rib marrow cavity and local soft tissue components, suggesting possible bone infiltration or extension through Haversian canals.
Based on the patient’s presentation (23-year-old male), right chest wall pain, and imaging findings (bone destruction with a soft tissue mass), the following should be considered:
Considering the patient’s age, symptoms (persistent chest wall pain), imaging findings (rib destruction, soft tissue mass, heterogeneous enhancement), and (as indicated by clinical and pathological evidence) the characteristic chromosome 11;22 translocation, the most likely diagnosis is:
Askin Tumor (part of the Ewing Sarcoma family).
A definitive diagnosis still requires histopathological examination (biopsy) and possibly molecular biological tests.
1. Treatment Strategy:
• (Neo)Adjuvant Chemotherapy: A standard multi-agent chemotherapy regimen is typically used to shrink the lesion and eliminate micro-metastases.
• Surgical Resection: For well-localized and resectable lesions, aggressive surgical intervention is recommended to achieve complete tumor resection while preserving necessary chest wall structure and function.
• Radiotherapy: Considered based on the extent of the lesion, surgical resection status, and patient condition, to help control local recurrence.
2. Rehabilitation and Exercise Prescription:
• General Principles: Since the lesion is located in the chest wall, careful attention should be paid to thoracic stability as well as post-operative (or post-radiotherapy) chest wall pain and functional limitations. Rehabilitation training should follow an individualized, stepwise (FITT-VP) approach:
- Frequency: 3-5 times per week, adjusted according to treatment tolerance and recovery status.
- Intensity: Start at low to moderate intensity (target heart rate 40-60% of maximum) and increase gradually based on pain tolerance and respiratory function.
- Time: Begin with 15-20 minutes per session, gradually extending to 30 minutes or longer, ensuring adequate rest intervals.
- Type: Focus on safe, easily performed aerobic exercises such as brisk walking, stationary bike riding, light resistance training, and breathing exercises.
- Progression: As the condition improves and the body adapts, increase exercise intensity or duration under professional guidance.
• Postoperative/Post-radiotherapy Considerations:
- Monitor chest wall pain and restricted breathing. Gradually introduce chest expansion and deep breathing exercises.
- Track changes in fitness levels, sweating, and heart rate. If fatigue or significant discomfort occurs, rest and reduce the exercise load accordingly.
- Conclude each session with gentle full-body stretching and relaxation to promote circulation and reduce soreness.
Disclaimer:
This report is based on existing imaging and available information, provided for reference only. It should not replace an in-person consultation or professional diagnosis and treatment advice from a qualified medical practitioner. If there are any questions or changes in your condition, please seek prompt evaluation from the relevant specialist.
Ewing’s sarcoma of the chest wall or Askin tumour.
