Primary synovial sarcoma of the lung as an incidental finding.

Synovial sarcoma of the lung (SSL) is a very rare but aggressive primary lung tumor. Due to its unusual histological features, it can easily be misdiagnosed, if only small biopsies of the tumor are investigated. Here, we review two recent cases of SSL diagnosed and treated in our institution. The first case is a 37-year-old male with a round nodule in the right lower lobe; he underwent a lobectomy. Histologically, the nodule resembled a biphasic tumor. Cytogenetic analysis revealed a translocation t (X; 18), and the diagnosis of primary SSL could be established. The patient is alive and disease-free since 45 months following surgery. The second case is a 41-year-old male with a cystic lesion in the right lower lobe, removed by video-assisted thoracic surgery (VATS) segmentectomy. In the tumor tissue, spindle cell-rich and cystic structures could be found, together with epithelial elements. Because the tumor contained also a translocation t (X; 18), it could be diagnosed as monophasic SSL. The patient is alive and disease-free since 11 months. Since rare diseases of the lung may present as subtle and focal changes, complete removal of suspect pulmonary lesions is always advisable.