Extraskeletal Ewing sarcoma

Extraskeletal Ewing Sarcoma

Extraskeletal Ewing sarcoma (EES) is a rare and aggressive form of cancer that originates in the soft tissues outside of the bone. It is part of the Ewing sarcoma family of tumors, which also includes Ewing sarcoma of the bone and Askin tumor.

Epidemiology

EES is a rare condition, accounting for a small percentage of all Ewing sarcoma cases. It primarily affects children and young adults, with a peak incidence between the ages of 10 and 20. The disease shows a slight male predominance.

Pathophysiology

EES is characterized by the presence of small round blue cells, similar to those found in Ewing sarcoma of the bone. The tumor is often associated with a specific chromosomal translocation, t(11;22)(q24;q12), which results in the EWSR1-FLI1 fusion gene. This genetic alteration is a hallmark of the Ewing sarcoma family of tumors.

Clinical Presentation

Patients with EES typically present with a rapidly growing mass in the soft tissues. Common sites include the trunk, extremities, and retroperitoneum. Symptoms may include pain, swelling, and occasionally systemic symptoms such as fever and weight loss.

Diagnosis

The diagnosis of EES involves a combination of imaging studies, histopathological examination, and molecular testing. Imaging techniques such as MRI and CT scans are used to assess the extent of the tumor. A biopsy is necessary to confirm the diagnosis, and molecular testing can identify the characteristic EWSR1-FLI1 fusion gene.

Treatment

The treatment of EES typically involves a multimodal approach, including surgery, chemotherapy, and radiation therapy. The specific treatment plan depends on the size, location, and extent of the tumor, as well as the patient's overall health. Chemotherapy regimens often include agents such as vincristine, doxorubicin, cyclophosphamide, and ifosfamide.

Prognosis

The prognosis for patients with EES varies depending on several factors, including the size and location of the tumor, the presence of metastases, and the response to treatment. Overall, the prognosis is similar to that of Ewing sarcoma of the bone, with a 5-year survival rate of approximately 50-70% for localized disease.

Research and Future Directions

Ongoing research is focused on improving the understanding of the molecular biology of EES and developing targeted therapies. Clinical trials are exploring the use of novel agents and immunotherapies to improve outcomes for patients with this rare disease.

See Also

• Ewing sarcoma
• Askin tumor
• Soft tissue sarcoma

External Links

• [National Cancer Institute - Ewing Sarcoma](https://www.cancer.gov/types/bone/patient/ewing-treatment-pdq)
• [American Cancer Society - Ewing Family of Tumors](https://www.cancer.org/cancer/ewing-tumor.html)

NIH genetic and rare disease info

• NIH info on Extraskeletal Ewing sarcoma

Extraskeletal Ewing sarcoma is a rare disease.