Primary pulmonary synovial sarcoma: a rare primary pulmonary tumor

Pulmonary sarcomas overall are very uncommon and comprise only 0.5 % of all primary lung malignancies. The diagnosis is established only after sarcoma-like primary lung malignancies and a metastatic extrathoracic sarcoma have been excluded. Synovial sarcoma accounts for ~8 % of soft-tissue sarcomas. Synovial sarcoma arising from the pleura has rarely been reported.

We report a case of a 58-year-old woman who complained of right-sided chest pain and shortness of breath. Chest CT scan revealed a large heterogeneous mass, occupying most of the right hemithorax. Histologic diagnosis was supplemented by interphase cytogenetic (FISH) analysis.

Computed tomography guided Tru-cut biopsy was suspicious for a sarcomatous or fibrous malignancy. However, intraoperative frozen-section diagnostics confirmed the diagnosis of a sarcoma. Immunohistochemistry showed that tumor cells expressed epithelial membrane antigen, CD99 and BCL2. Based on immunohistochemistry, the diagnosis of synovial sarcoma was suspected and was confirmed by FISH analysis. The patient was treated with right upper bilobectomy. Due to R1-resection status, postsurgical systemic chemotherapy was administered.

Primary pulmonary synovial sarcoma is a rare primary lung tumor. Due to extensive size of the tumor with pleural and mediastinal invasion only a R1-resection status could be achieved by thoracic surgery.