# Ewing Sarcoma Family of Tumors (ESFTs) of Renal Origin Presenting With Bone Metastases: A Case Report

## TL;DR

A rare case of kidney cancer linked to Ewing sarcoma family tumors with bone metastases is reported, highlighting the importance of considering this diagnosis in aggressive kidney tumors.

## Contribution

This case report adds to the limited literature on Ewing sarcoma family tumors originating in the kidney.

## Key findings

- The patient had a kidney mass and bone metastases confirmed as Ewing sarcoma family tumors.
- Molecular analysis revealed a type II EWSR1:FLI1 gene fusion.
- The disease progressed rapidly, leading to the patient's death within three months.

## Abstract

We report a unique case of a female patient in her fifth decade of life who presented with groin pain and was found to have a right kidney mass measuring approximately 8 cm, in addition to multiple bone metastases. Both the nephrectomy specimen and the bone biopsy were found to belong to the Ewing sarcoma family of tumors (ESFTs). This was confirmed by immunohistochemical studies and fluorescence in situ hybridization (FISH) showing EWSR1 gene rearrangement. Molecular analysis with next-generation sequencing (NGS) showed a type II EWSR1:FLI1 gene fusion. The patient’s disease progressed rapidly, and she passed away approximately three months after admission. Although extremely rare in the kidney, ESFT should be considered in patients who present with clinically aggressive kidney tumors.