Pericardial synovial sarcoma: challenges in diagnosis and management

Introduction: Pericardial synovial sarcoma is an extremely rare tumor with poor prognosis. Timely diagnosis and aggressive multimodal management improves patient outcome. We present our experience of diagnosis and management of a young patient with monophasic synovial sarcoma arising from pericardium. Case: A 27-year-old man presented with dyspnea and cough of three weeks duration. Examination revealed sinus tachycardia, distant heart sounds and elevated jugular venous pressure. Chest X-ray showed widened mediastinum. Transthoracic echocardiogram (TTE) noted large pericardial effusion with tamponade physiology. Therapeutic pericardiocentesis yielded hemorrhagic fluid. Computed tomography (CT) of the chest showed persistent pericardial effusion and a left anterior mediastinal mass. Left anterior thoracotomy, pericardial window and left anterior mediastinotomy were done, revealing a well-encapsulated gelatinous tumor originating from the pericardium. Histology and immunohistochemical profile showed the tumor to be a monophasic synovial sarcoma. Fluorescent in-situ hybridization (FISH) was positive for SS18 (SYT) gene rearrangement on chromosome 18q11, substantiating the diagnosis. Work-up for metastases was negative. Neo-adjuvant chemotherapy with high dose ifosfamide led to substantial reduction in the size of the tumor. The patient underwent surgical resection and external beam radiation therapy (EBRT) post surgery. He had symptom-free survival for 8 months prior to local recurrence. This was managed with left lung upper lobectomy and follow-up chemotherapy with docetaxel. The patient is currently stable with an acceptable functional status. Conclusion: In patients with pericardial effusions of unknown etiology, multiple modalities of cardiac imaging must be employed if there is suspicion of a pericardial mass. CT and magnetic resonance imaging (MRI) are useful to evaluate for pericardial thickening or masses in addition to TTE. Treatment of synovial sarcoma is not well established. Surgery is the cornerstone of treatment. In non-resectable tumors, aggressive neo-adjuvant chemotherapy with ifosfamide followed by surgical resection and EBRT may lead to improved outcome.