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 well-defined 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, immunohisto-chemical, and molecular studies of primary pulmonary synovial sarcoma.