A80-4-48 Synovial Sarcoma With Metastatic Cavitary Pulmonary Lesions

Abstract Synovial sarcomas are a rare soft tissue cancer that commonly present as a slow growing mass in the extremities near large joints and occur mainly in adolescents and young adults. The most common location of metastases is the lungs. Radiologically, lung metastases have been characterized primarily as solid non-cavitary lesions. We present a case of metastatic synovial sarcoma that was found to have extensive cavitary and cystic pulmonary metastases. A 35-year-old female was diagnosed one year prior with synovial sarcoma of the left leg with pulmonary metastasis. She was seen in the Emergency Room after a computed tomography (CT) of her chest that was done for staging purposes showed pneumomediastinum. After leaving against medical advice, she returned two days later with progressive dyspnea. A repeat CT chest showed persistent pneumomediastinum with bilateral extensive large pleural and non-pleural based predominantly cavitary and cystic lesions as described in Figures A-D. Interventional pulmonology was consulted for persistent pneumomediastinum and pleural effusion who recommended conservative therapy without intervention. The patient developed altered mental status with worsening acute hypoxic hypercapnic respiratory failure and ultimately was made comfort care before passing away at the hospital. Synovial sarcoma with metastases occurs in up to 54% of patients, of those patients lung involvement is seen in up to 90%. The predominant radiologic features on CT chest of metastatic synovial sarcoma are round or oval pleural-based masses with heterogenous enhancement. There are few case reports of metastatic synovial sarcoma exhibiting cystic and cavitary features. However, primary pleuropulmonary synovial sarcoma does present with cystic and cavitary pulmonary lesions in up to 41% of cases. We share this case of metastatic synovial sarcoma with atypical thoracic radiologic features in hopes to raise awareness of this differential when encountering cavitary and/or cystic lung lesions as well as acknowledging this as a characteristic of synovial sarcoma thoracic disease. This abstract is funded by: None