Ewing Sarcoma is Malignant, Not Benign
Ewing sarcoma is definitively a malignant, high-grade cancer—never benign—and represents the second most common primary malignant bone tumor in children, adolescents, and young adults. 1
Malignant Nature and Biological Behavior
- Ewing sarcoma is classified as a high-grade malignancy in all cases, with no low-grade or benign variants existing. 1
- This tumor is an aggressive small round blue cell malignancy that belongs to the Ewing family of tumors, likely of neurogenic origin. 2, 3
- Without multimodal treatment including chemotherapy, 5-year survival is less than 10%, demonstrating its lethal nature. 1
- Between 20-25% of patients present with metastatic disease at diagnosis, most commonly to lungs (10%), bones/bone marrow (10%), or combinations thereof. 1, 4
Clinical Presentation in Your Patient
For a 24-year-old male with a clavicular growth, this presentation is consistent with Ewing sarcoma demographics and behavior:
- The median age at diagnosis is 15 years, but the disease occurs in adolescents and young adults, making your 24-year-old patient within the typical age range. 1, 4
- Ewing sarcoma can involve any bone, including the clavicle, though 50% occur in extremity bones and 20% in pelvic bones. 1
- The first symptom is typically pain, often mistakenly attributed to trauma. 1
Diagnostic Confirmation Required
This patient requires immediate referral to a specialized bone sarcoma center before any biopsy is performed to prevent tissue plane contamination. 5, 6
- Plain radiographs in two planes should be obtained first, followed by MRI of the entire involved bone and CT chest for staging. 1, 5
- Definitive diagnosis requires biopsy showing small round blue cells that are PAS-positive and CD99 (MIC2)-positive on immunohistochemistry. 1, 5
- Molecular testing demonstrating EWS gene rearrangements (typically t(11;22)(q24;q12) in most cases) is diagnostic and present in >90% of cases. 1, 5
Treatment Implications of Malignancy
- Current multimodality treatment combining chemotherapy with surgery and/or radiotherapy achieves 60-70% survival in localized disease. 1
- Treatment requires coordination by a specialized center using combination chemotherapy including doxorubicin, vincristine, ifosfamide, etoposide, dactinomycin, and cyclophosphamide. 5, 7
- Patients with metastatic disease have 5-year survival of 20-40%, except those with isolated pulmonary metastases who achieve approximately 50% survival. 7
Critical Pitfall to Avoid
The most dangerous error would be treating this as a benign lesion or performing biopsy at a non-specialized center, which can contaminate tissue planes and compromise subsequent surgical management, worsening outcomes in this already aggressive malignancy. 5, 6