# Chest Wall Synovial Sarcoma: A Unique Encounter at the Breast Base

## TL;DR

A rare case of synovial sarcoma in the chest wall was diagnosed in a young woman presenting with breast swelling.

## Contribution

This case highlights the unusual presentation of synovial sarcoma at the breast base.

## Key findings

- The lesion was located in the left pectoralis major and minor muscles, confirming a chest wall origin.
- Histopathology confirmed the diagnosis of monophasic synovial sarcoma.
- Imaging techniques like CECT and MRI were crucial in determining the tumor's location and characteristics.

## Abstract

Synovial sarcomas most commonly arise in the para-articular locations of the extremities, such as the upper limbs, thigh, knee, ankle, and foot. Thoracic synovial sarcomas are a rare entity that can arise in the chest wall, pleura, lung, heart, or mediastinum. We present a case of a 23-year-old female with a complaint of swelling of the left breast. Examination demonstrated an enlarged left breast and a hard-fixed swelling without overlying skin changes or nipple retraction. Ultrasound showed a well-defined, solid-appearing lesion deep in the left breast parenchyma, which was adherent to the underlying left chest wall musculature and seemed to be displacing the breast parenchyma anteriorly. Contrast-enhanced computed tomography (CECT) and magnetic resonance imaging (MRI) confirmed the lesion centered at the left pectoralis major and minor muscles, confirming the chest wall's origin. Histopathology findings favored monophasic synovial sarcoma.