# Extraskeletal Myxoid Chondrosarcoma With Rhabdoid Features in a Pediatric Patient

## TL;DR

A 12-year-old girl was diagnosed with a rare and aggressive tumor in her thigh that had spread to her lungs.

## Contribution

The case highlights the diagnostic challenges and the importance of integrating multiple diagnostic methods for accurate identification.

## Key findings

- The tumor was diagnosed using clinical, radiological, histopathological, and ultrastructural features.
- The tumor was associated with lung metastasis in a pediatric patient.
- NR4A3 rearrangement testing is not routinely performed due to limited technological availability.

## Abstract

Extraskeletal myxoid chondrosarcoma is an aggressive tumor in children. Due to its low incidence and nonspecific clinical presentation, as well as its radiological and histopathological characteristics, it is considered a diagnostic challenge. Furthermore, despite the NR4A3 rearrangement being specific to this neoplasm, its evaluation is not routinely performed, as few places have the technology to characterize it. We present the case of a 12-year-old girl with extraskeletal myxoid chondrosarcoma in the right thigh associated with lung metastasis. The diagnosis was ultimately made by integrating the clinical, radiological, histopathological, and ultrastructural features of the chondroblastic differentiation.