Primary Pulmonary Synovial Sarcoma: A Case Report

We report a rare case of primary synovial sarcoma of the lung. A 57-year-old man had a welldefined tumor in the right middle lobe seen on chest computed tomography, and underwent lobectomy. Grossly, the nonencapsulated tumor measured 4.5 cm in greatest diameter, with a solid and tan-white cut surface. Histologically, the tumor was mainly composed of a dense proliferation of spindle cells. Immunohistochemical studies were focally positive for epithelial membrane antigen, and diffusely positive for CD99 and Bcl-2. Cytokeratin, S-100 protein, desmin, smooth muscle actin, and CD34 were absent. SYT-SSX1 gene fusion transcript was detected by reverse transcription–polymerase chain reaction, which is diagnostic of primary synovial sarcoma of the lung. We also review the literature with regard to the clinicopathologic, immunohistochemical, and molecular studies of primary pulmonary synovial sarcoma.