Occult primary pulmonary synovial sarcoma presenting as recurrent spontaneous pneumothorax and explosive progression

Primary pulmonary synovial sarcoma (PPSS) is a relatively rare neoplasm with highly progressive potential. We present an extremely rare case of PPSS presenting as recurrent pneumothorax with bullous lesions. Bullectomy was performed at the local hospital. Unfortunately, the patient was initially misdiagnosed as atypical carcinoid. Although a negative resection margin was obtained during the first surgery and a remedial operation and chemotherapy followed, the patient developed severe disease progression and died soon after. This report demonstrates that PPSS can easily be misdiagnosed and should be seriously considered in the differential diagnosis of pneumothorax.