Extraskeletal Ewing sarcoma: Diagnosis, management and prognosis

Abstract

Extraskeletal Ewing sarcoma (EES) is a relatively uncommon primary tumor of the soft tissues, which accounts for 20-30% of all reported cases of ES. Being uncommon, all members of the ES family tumors are treated following the same general protocol of sarcoma tumors. The present review summarizes the diagnosis, management and prognosis of EES, focusing on the differences between the subtypes of ESS. The clinical features and imaging of EES are also discussed. Magnetic resonance imaging is the modality of choice for diagnostic imaging and local staging, while core-needle biopsy with pathological testing is used to obtain a definitive diagnosis. Although several oncology groups endorse that ES family of tumors should be treated with similar algorithm and protocols, some studies have demonstrated that surgery and radiotherapy may be used as a form of local control. However, further studies are required to conclude the optimum treatment option for EES.

Keywords: Ewing sarcoma; diagnosis; prognosis; therapy.

Figure 1.

Axial selective suppression of fat gadolinium-based contrast agent magnetic resonance image of the left shoulder of a 16-year-old woman with extraskeletal Ewing sarcoma (A) pre- and (B) post-chemotherapy treatment.

Figure 2.

Images of the left shoulder of a 16-year-old woman with extraskeletal Ewing sarcoma. (A) Hematoxylin and eosin staining presents uniform round blue cells infiltrating soft tissue in a random distribution (magnification, ×20). (B) NSE in addition to CD99 positivity demonstrated that the tumor cells were positive for NSE (magnification, ×20). NSE, neuron specific enolase staining.

Figure 3.

Images of the left distal thigh of a 20-month-old girl with extraskeletal Ewing sarcoma. (A) Hematoxylin and eosin staining of Ewing sarcoma involving fibroadipose tissue and skeletal muscle (magnification, ×10). (B) Hematoxylin and eosin staining of tumor cells demonstrated high NC ratio, with indistinct cytoplasmic borders (magnification, ×40). (C) Infiltrate demonstrating strong membranous positivity for CD99 (magnification, ×40). (D) Positive staining for neural marker synaptophysin (magnification, ×40). NC, nuclear-cytoplasmic.