# Undifferentiated High-Grade Pleomorphic Sarcoma of the Posterior Mandible: A Report of a Rare Case

## TL;DR

A rare case of a high-grade jaw tumor was initially mistaken for a benign lesion, highlighting the need for thorough testing and imaging for accurate diagnosis.

## Contribution

The paper presents a rare case emphasizing the diagnostic challenges of UPS mimicking benign lesions in the mandible.

## Key findings

- UPS can mimic benign lesions like CGCG on limited biopsies.
- Aggressive imaging features and extended immunohistochemistry are critical for accurate diagnosis.
- Adequate tissue sampling and multidisciplinary evaluation are essential for destructive mandibular lesions.

## Abstract

Undifferentiated pleomorphic sarcoma (UPS) is a high-grade mesenchymal malignancy that can closely resemble benign giant-cell-rich lesions such as central giant cell granuloma (CGCG), especially on limited biopsies. We report a case of a female patient with an enlarging mandibular swelling and an expansile osteolytic lesion that was initially diagnosed as CGCG based on an incisional biopsy showing multinucleated giant cells in a fibroblastic stroma. However, extended immunohistochemistry and the aggressive radiologic features supported a revised diagnosis of giant-cell-rich variant UPS. This case highlights the potential for diagnostic confusion on insufficient samples and emphasizes the importance of adequate tissue sampling, correlation with imaging, and comprehensive ancillary testing when evaluating destructive mandibular lesions.