INTRODUCTION: Synovial sarcoma is a rare soft tissue tumor involving the extremities and limb girdles and is seen in young adults. It metastasizes in 30-40 % of cases and lung is a frequent site of metastases. Reported cases include presentations as a single large lung mass, multiple metastatic lung nodules- with or without involvement of the mediastinum, pericardium or diaphragm, and lung metastases simulating a granuloma. We report a case which presented as a spontaneous pneumothorax. Further investigations revealed a metastatic synovial sarcoma after 11 years of remission.
CASE PRESENTATION: A 38-year-old African American male presented to the hospital with acute onset of sharp right-sided chest pain and dyspnea. The initial chest film revealed a tiny right apical pneumothorax, less than 10%, which was managed conservatively in the hospital by observation and nasal-flow oxygen for the next 24 hours. The patient had no prior history of chest surgery, chest trauma, heart failure, recent pulmonary infection, or congenital lung abnormality.Past medical history included surgical resection and radiation of a synovial sarcoma presenting as a 6.7 x 7.3 cm oval-shaped mass in the right lower quadrant of the abdominal wall 13 years prior. Two years later a recurrence on the right iliac crest required a curative surgical resection followed by brachytherapy. He was reported to be in remission on regular follow up appointments for the next 5 years.Family history was unremarkable. Social history revealed that he was a non-smoker, a full time engineering student with no history of exposure to asbestos or environmental toxins.Physical exam: A healthy-appearing man, with normal breath sounds and exam unremarkable except for prior surgical scars.Lab data: Unremarkable except for a WBC count of 3.4 x 103 cells/μL with normal differential count. Hospital course: Further work up included a CT scan of the chest with pulmonary embolism protocol, negative for PE, but revealing a triangular 2.9 x 2 cm opacity in the right major fissure, raising the possibility of a pseudotumor due to fluid in the fissure. Symptoms resolved without further intervention, and the patient was discharged from the hospital.Subsequent course: He returned to the outpatient pulmonary clinic 10 days later. A follow-up CT scan revealed persistence of the opacity in the right major fissure, and another 1.3 cm pulmonary nodule in the left lower lobe. A CT guided biopsy of the right sided lesion revealed a metastatic synovial sarcoma of monophasic type. Cytogenetic evaluation using DNA FISH technology demonstrated a rearrangement of the SS18 (18q11.2) gene in 64% of nuclei. This probe hybridizes to band 18q11.2 (SS18) confirming translocation (X;18) for synovial sarcoma. A thoracic surgery consultation led to uneventful right axillary thoracotomy with wedge resection of the mass involving right middle and right lower lobe for metastasectomy with curative intent. A wedge resection of the left sided nodule is pending in the coming month.
DISCUSSIONS: Synovial sarcoma is a spindle cell tumor of soft tissues with a high propensity for pulmonary metastasis though primary pleural malignancy has also been described. Though our case represented metastatic disease, it is unusual in its presentation as a pneumothorax with only a few cases previously reported. The usual differential diagnosis of an opacity in the major fissure includes loculated fluid, blood, pus, and inflammatory cells, with malignancy less likely. In our case, concern for malignancy required careful history-taking and a high index of suspicion of a pneumothorax secondary to sub-pleural pulmonary metastasis.
CONCLUSION: Metastatic synovial sarcoma with pulmonary involvement can present after several years of remission and should be suspected in a patient with a known history of synovial cell sarcoma .
DISCLOSURE: Rupesh Dave, No Financial Disclosure Information; No Product/Research Disclosure Information