INTRODUCTION: Pulmonary synovial sarcomas are extremely rare tumors with no predilection for tumor location, usually affecting young males. Their clinical prognosis is largely unknown. We describe the first case of primary synovial sarcoma of the lung with direct, intracardiac extension.
CASE PRESENTATION: A 53 y/o WM treated with mantle radiation for Hodgkin's Lymphoma 13 years ago presented with 6 weeks of nonproductive cough. He denied dyspnea and ran 3 miles on a treadmill daily without limitation. He denied chest pain, palpitations, orthopnea, fevers, chills or gastroesophageal reflux symptoms. Past medical history was significant for only Hodgkin's lymphoma. He never smoked, and denied alcohol or illicit drug use. Review of systems was unremarkable. Vital signs and physical examination were notable for diminished breath sounds in the right upper chest. Heart exam was normal. Chemistries and CBC were unremarkable. Echocardiogram revealed a normal ejection fraction and a large left atrial mass 4.4 × 2.6 cm originating from the right superior pulmonary vein and appeared to traverse the mitral valve with moderate mitral regurgitation. PFTs showed mild restriction with a normal diffusing capacity. Chest X-ray demonstrated a 10 X 9 cm large round opacity in the right upper lobe and anterior mediastinum. MRI demonstrated a large mass in the right upper lobe with invasion of the right superior pulmonary vein and left atrium. The patient subsequently underwent a right pneumonectomy and primary resection of the left atrial and pulmonary vein invasion. On gross examination of the right lung, there was a well circumscribed tan white soft mass (8 X 8 X 7.5 cm) with focal areas of necrosis. The intracardiac mass was oval shaped, nodular tissue with a smooth surface (7 X 3 X 2 cm) weighing 28 grams. Microscopically, it was monophasic pulmonary synovial sarcoma which stained positive for vimentin, BCL-2 and epithelial membrane antigen. Molecular studies performed on submitted tissue were positive for the SYT-SSX gene.
DISCUSSIONS: Synovial sarcomas are soft tissue tumors of uncertain histogenesis, usually arising in the vicinity of large joints. Rarely, they have been described in the head/neck, chest and abdomen. Pulmonary sarcomas are rare (<0.5% of lung tumors) and are usually metastases from other primaries (leiomyosarcomas, fibrosarcomas and heamangiopericytomas). Usually, they present as a large (2–15 cms) well defined mass in an asymptomatic patient found on routine X-ray. About 60 cases have been reported so far in literature and only 11 have been confirmed by the definitive molecular detection of SYT-SSX fusion gene transcription. T(X;18)(p11.2;q11.2) translocation results from fusion of SYT gene on Chr 18 to either SSX1 or SSX2 on Chr X. SYT-SSX1 has a worse prognosis with a 5 yr survival rate of 42 vs. 89% (for SSX2). Histologically, they are classified into four subtypes: biphasic, monophasic fibrous, monophasic epithelial, and poorly differentiated. These tumors stain frequently for epithelial markers such as cytokeratin and/or epithelial membrane antigen; vimentin and CD99. Diagnosis can be made on clinical, histological and immunohistochemical evaluation, and molecular testing is not required in all cases. Clinical course is largely unknown with a reported mortality rate up to 55% in a large case series of 25 patients. Intracardiac extension has not been previously reported. Our patient had successful extraction of the intracardiac mass with right pneumonectomy, and remains in clinical remission 6 months post-operatively.
CONCLUSION: This is the first described case of primary synovial sarcoma of the lung with an intracardiac extension. Since prior reported cases showed no particular predilection of tumor location, we suggest cardiac evaluation for synovial sarcomas with mediastinal involvement.
DISCLOSURE: Veena Devarakonda, None.