INTRODUCTION: Synovial Sarcomas are soft tissue tumors which are usually found in the extremities. However, they have been described in unusual locations, with mesenchymal cell origins. Most pleural synovial sarcomas are metastatic and ‘primary’ pleural synovial sarcomas are rare .They are frequently misdiagnosed as relatively more common entities, such as malignant mesothelioma. We describe a case of pleural synovial sarcoma in a patient with recurrent pleural effusion, treated initially presumptively as tuberculosis (TB).
CASE PRESENTATION: A 37 year female was referred for evaluation of a nonresolving left sided exudative hemorrhagic effusion. Her history was significant 6 kg. weight loss over 3 months, dry cough and breathlessness. She had thoracentesis previously at another center, with 1.5 L of a lymphocytic exudate drained and treated empirically as TB, as is common in the Indian subcontinent. A chest tube was placed later for recurrent large effusion. Clinical exam showed absent breath sounds on the left side, with a chest tube draining about 400 ml/day. Pericardial effusion was ruled out by echocardiogram. CT chest showed two 1-2 cm nodular lesions in right lung, large lobulated mass in left posterior hemi thorax, left hydropneumothorax with chest tube in situ, and adenopathy in left cardiophrenic space. We proceeded with medical thoracoscopy and drained about 1400 ml of hemorrhagic fluid. Thoracoscopy showed a hemorrhagic pleural surface, with a visceral pleural mass. Cautious biopsies were done, and the mass opened in layers, giving an onion peel-like appearance. Histopathology showed tumor cells with scanty ill-defined cytoplasm, spindle cells with oval nuclei and mild pleomorphism. Immunohistochemistry identified the tumor as pleural synovial sarcoma.The chest tubes were removed on day 3. She was started on chemotherapy consisting of Adriamycin and ifosfomide. She received 6 cycles of chemotherapy. She improved significantly, with remarkable decrease in the tumor size, and no recurrence of the effusion.
DISCUSSIONS: Primary pleural sarcomas comprise <1% of all primary lung malignancies.Synovial sarcomas are rare tumours, occasionally arising in the pleural cavity. Their histological characteristics may be mistaken for those of malignant mesothelioma or other spindle cell tumors. Diagnosis is made by histology and immunohistochemistry. Identification of the synovial sarcoma-specific chimeric transcript (SYT-SSX1 or SYT-SSX2), with immunoperoxidase studies, are critical in identifying cases of pleural monophasic synovial sarcoma. Synovial sarcoma is extremely aggressive with a high incidence of recurrence. Prognosis is poor; with an overall 5-year survival rate of 50%.Our patient has done well on the chemotherapy regimen outlined earlier.
CONCLUSION: This case is one of the few case reports of primary pleural synovial sarcoma described in literature. Interesting points include misidentification for commoner conditions like TB in the Indian subcontinent, which delays the diagnosis. Here, the role of medical thoracoscopy was vital in making an accurate diagnosis and in conjunction with accurate immunohistochemistry led to a diagnosis, which helped to streamline management. Another interesting issue was the sampling of a mass in the visceral pleura, which is not commonly done. This was possible due to a clear avascular surface tumor on the visceral pleura, which was biopsied cautiously, with no complications. In our case, arriving at the correct diagnosis, with contemporary interventional pulmonology methods, and chemotherapy has improved the outcome of this otherwise aggressive tumor.
DISCLOSURE: Lakshmi Priya Srinivasan, No Financial Disclosure Information; No Product/Research Disclosure Information