Abstract
Synovial sarcoma is a highly malignant tumor that accounts for 10% of all soft tissue sarcomas. Primary pulmonary synovial sarcoma (PPSS) is extremely rare, and its prognosis is poor. A diagnosis is usually established after other primary lung malignancies or metastatic extrathoracic sarcomas have been excluded. Therefore, it is often misdiagnosed. In this study, we report the case of a 38-year-old woman who was misdiagnosed as having pleural mesothelioma and finally endured surgery to remove the tumor. The tumor showed SYT-SSX fusion transcripts and was diagnosed as PPSS after combining histopathological and immunohistochemical analyses. Finally, we determined some biomarkers through whole-exome sequencing (WES) to improve the diagnosis and treatment strategies.