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A6679 - Deadly Imposter: A Rare Pleural Tumor Masquerading as Pulmonary Abscess
Author Block: E. E. O'Shea Paudel, S. E. Kopec; Pulmonary, Allergy and Critical Care, University of Massachusetts Medical Ctr., Worcester, MA, United States.
Introduction: Synovial sarcoma is an uncommon, aggressive tumor, usually arising from soft tissue adjacent to large joints. It rarely arises from the pleura, lung or mediastinum. Synovial sarcomas arising from the pleura can present as pleural masses, pleural thickening, pleural effusion, or pneumothorax. We present a case of a patient with a large, rapid accumulating exudative effusion with an underlying fluid-filled mass initially suspicious for lung abscess, but ultimately found to be a synovial sarcoma of the pleura.
Case: A 46-year-old female presented to with dyspnea, cough and left sided chest pain for one month. She had been treated as an outpatient with two courses of azithromycin for presumed pneumonia. Despite treatment her symptoms worsened and, work-up revealed a left-sided pleural effusion. Her dyspnea was relieved after drainage of 1.6L exudative effusion with negative cytology and cultures. CT chest performed after thoracentesis showed a rounded, localized area of fluid with an air-fluid level at the medial left lung base, felt consistent with a lung abscess. After 10 days of therapy with azithromycin and cefpodoxime she returned with severe dyspnea and was found to have rapid reaccumulation of the pleural effusion. It was drained again of 1.8L exudative fluid with negative cultures and cytology. Six days later and was re-admitted after a repeat chest CT demonstrated re-accumulation of the fluid, and new evidence of loculations. A chest was placed draining another 2.3L overall with pleural thrombolytics. Serial CT scans demonstrated decreased size of the effusion, but increased size of the posteromedial collection suggestive of abscess. After consultation with thoracic surgery, the patient opted for a conservative treatment approach with a prolonged course of antibiotics. The chest tube was discontinued and she was discharged home on oral antibiotics to complete a four-week course. After reporting initial improvement, she was re-admitted one month later with worsening chest pain and dyspnea. She underwent an open thoracotomy with total left pulmonary decortication. Analysis of pleural tissue revealed malignant spindle cell proliferation consistent with monophasic synovial sarcoma. Subsequent PET scan showed a soft tissue mass and several subpleural nodules encasing the left lung. Systemic Doxorubicin and Ifosfamide was initiated.
Discussion: Pleural synovial sarcoma is a rare and aggressive tumor which should be considered, along with other pleural tumors, in patients who have rapid accumulation of pleural effusion and who are not responding predictably to usual therapy. Unfortunately, with limited treatment options, survival is poor.