Primary Cystic Pleuropulmonary Synovial Sarcoma Presenting as Recurrent Pneumothorax.

Primary pleuropulmonary synovial sarcomas are quite rare, representing 0.1-0.5% of all pulmonary malignancies. We report an entirely cystic monophasic synovial sarcoma in a 25-year-old male who presented with recurrent pneumothorax and no evidence of a mass lesion on imaging. The purpose of this case report is to increase awareness of neoplasms clinically presenting as a pneumothorax with no imagining evidence of a mass-forming lesion and emphasize the significance of fluorescent in situ hybridization testing in nontypical synovial sarcoma cases.