What is Ewing Sarcoma?

Ewing Sarcoma
Fluorescence in situ hybridisation for EWSR1 gene rearrangement, and histology of variant Ewing sarcoma types. (A) Fluorescence in situ hybridisation using dual-colour break-apart probes which flank the EWSR1 breakpoint region on chromosome 22q12. The nucleus of this neoplasm contains separated (split) red and green signals indicating a rearrangement involving the EWSR1 gene at 22q12. A fused normal signal is also present, denoting the site of the EWSR1 gene. (B and C) Ewing sarcoma. These are examples of Ewing sarcomas with morphologic features that can cause diagnostic difficulty, particularly as they can show immunophenotypical overlap with other round cell neoplasms. (B) Ewing sarcoma with a well-defined nested architecture and areas of cellular discohesion mimicking alveolar rhabdomyosarcoma; (C) Ewing sarcoma with irregular cellular nests in prominent desmoplastic stroma, mimicking desmoplastic small round cell tumour, and (D) large cell Ewing sarcoma. RT–PCR in each case was diagnostically contributory, as this showed the presence of EWSR1-FLI1 fusion transcripts diagnostic of Ewing sarcoma. The spectrum of EWSR1 -rearranged neoplasms at a tertiary sarcoma centre; assessing 772 tumour specimens and the value of current ancillary molecular diagnostic modalities. British Journal of Cancer. Not Altered. CC.

Ewing sarcoma is a type of tumor that forms in bone or soft tissue and may be found in the bones of the legs, arms, feet, hands, chest, pelvis, spine, or skull.

What is the Pathology of Ewing Sarcoma?

 The pathology of Ewing sarcoma is:

–Etiology: The cause of Ewing sarcoma is: It’s not inherited, but it can be related to non-inherited changes in specific genes during a person’s lifetime. When chromosomes 11 and 22 exchange genetic material, it activates an overgrowth of cells. This may lead to the development of Ewing’s sarcoma.

–Genes involved: Translocation of EWSR1 gene on chromosome 22 and the FLI1 gene on chromosome 11.

–Pathogenesis: The sequence of events that lead to Ewing sarcoma involves the EWS/FLI protein has the DNA-binding function of the FLI protein as well as the transcription regulation function of the EWS protein. It is thought that the EWS/FLI protein turns the transcription of a variety of genes on and off abnormally. This dysregulation of transcription leads to uncontrolled growth and division and abnormal maturation and survival of cells, causing tumor development.

–Morphologic changes: The morphologic changes involved with Ewing sarcoma are small round blue cells.

How does Ewing Sarcoma Present?

Patients with Ewing sarcoma are typically males between ages of 10 to 20 years old. The symptoms, features, and clinical findings associated with Ewing sarcoma include pain, swelling, fever, weight loss, and potentially paralysis if the tumor is in the spinal region.

How is Ewing Sarcoma Diagnosed?

Ewing sarcoma is diagnosed by CT scan, X-rays, ultrasound, MRI, and biopsy.

How is Ewing Sarcoma Treated?

Ewing sarcoma is treated by surgery, radiotherapy, or chemotherapy

What is the Prognosis of Ewing Sarcoma?

The prognosis of Ewing sarcoma is good. About 70 percent of children with Ewing sarcoma are cured. Teens aged 15 to 19 have a lower survival rate of about 56 percent. For children diagnosed after their disease has spread, the survival rate is less than 30 percent.

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Last updated on May 26, 2022