PRIMARY INTRATHORACIC SYNOVIAL SARCOMA

Abstract

TOPIC: Lung Cancer TYPE: Medical Student/Resident Case Reports INTRODUCTION: Synovial sarcomas (SS) are a rare group of malignancies, seen in 0.17 per 100,000 persons, accounting for 7% of all soft tissue sarcomas. These malignant tumors most commonly present as a tumor of the extremities. While they have a high propensity for metastasis to bone and lung, primary intrathoracic malignancy is rare. We present a case of a patient who presented with acute onset shortness of breath, diagnosed with primary synovial sarcoma of the lung. CASE PRESENTATION: A 22-year-old male with no past significant medical history presented with a four-week history of right upper quadrant abdominal pain and acute onset chest pain radiating to his shoulder with associated dyspnea. On arrival to emergency department, patient was tachycardia, otherwise vitally stable. Labs were notable for leukocytosis. Chest x-ray showed a moderate right-sided pleural effusion with associated opacity of the lower hemithorax. A chest tube was placed however no fluid was evacuated. A CT of the chest was obtained which showed a right lower lobe hemithorax, a right lower lobe pleural-based nodule measuring 2x2 x 1.6 cm, and a lesion within the right hemithorax measuring 20x17.9x19.3 cm. The patient was taken for video-assisted thoracoscopic surgery for surgical exploration and chest tube placement. Patient was found to have large tumor invading whole right chest with compression on mediastinal structures including the heart, lung, and IVC. Biopsies were taken. Patient developed acute respiratory distress and obstructive shock and was intubated and placed on vasopressor support. Preliminary pathology was revealing of synovial sarcoma. Operative findings revealed a large right pleural and posterior mediastinal mass invading the right lower lobe through the diaphragm into the peritoneal space and liver capsule. He underwent thoracotomy with excision and resection of the thoracoabdominal and mediastinal tumor, total pulmonary decortication, wedge resection of right lower and middle lobe, and reconstruction of diaphragm. The patient was successfully extubated three days post operatively and soon after discharged home. Post-operative CT showed no definite evidence of gross residual disease. The patient received 3 cycles of doxorubicin/isofosfamide following discharge. DISCUSSION: Reports of primary thoracic SS are rare. Diagnosis is often delayed because of the benign radiographic appearance and indolent nature of these tumors; sequelae of disease often do not manifest until tumor burden is great enough to cause mass effect. Though standard of care is chemotherapy, the patient in this case required emergency palliative resection due to cardiovascular compromise. CONCLUSIONS: Though soft tissue sarcomas account for less than 0.1% of all malignant thoracic neoplasms, it should be considered in the differential for thoracic malignancies as delay in diagnosis could be consequential to patient outcome. REFERENCE #1: Javad Parvizi, Gregory K. Kim, Chapter 218 - Synovial Sarcoma, Editor(s): Javad Parvizi, Gregory K. Kim, High Yield Orthopaedics, W.B. Saunders, 2010, Pages 455-456, ISBN 9781416002369, https://doi.org/10.1016/B978-1-4160-0236-9.00230-3. REFERENCE #2: Nedra Joseph, Samantha St. Laurent, Jeanenne Joy Nelson, Shan Zheng, and Heide Stirnadel-Farrant. Journal of Clinical Oncology 2019 37:15_suppl, e22535-e22535 DISCLOSURES: No relevant relationships by Neiha Kidwai, source=Web Response