# Extraskeletal Ewing Sarcoma: A Case Report

## TL;DR

A 42-year-old woman was diagnosed with a rare case of Ewing sarcoma in soft tissue, not bone, and showed a positive response to chemotherapy.

## Contribution

This case report highlights an unusual presentation of Ewing sarcoma in a middle-aged woman with a soft tissue mass.

## Key findings

- The tumor displayed a positive EWSR1 gene rearrangement via fluorescence in situ hybridization.
- The patient showed a favorable response to chemotherapy despite complications.
- This case contributes to understanding the atypical manifestations of Ewing sarcoma.

## Abstract

Ewing sarcoma is one of the most common primary bone tumors arising from neuroectodermal cells mainly presenting in the younger population. Instances of this highly malignant tumor manifesting outside of the bone and outside of the typical age range create an unfamiliar clinical scenario. In this report, we present a rare extraskeletal Ewing sarcoma in a 42-year-old woman with a subcutaneous soft tissue mass in the posterior chest displaying a positive EWSR1 gene rearrangement via fluorescence in situ hybridization. The patient is currently on a chemotherapy regimen showing favorable response to the tumor size despite additional complications. This overall presentation of Ewing sarcoma allows further understanding of the malignancy and fosters better care for future cases.