SESSION TITLE: Miscellaneous SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 31, 2017 at 01:30 PM - 02:30 PM INTRODUCTION: Ewing sarcoma is an uncommon malignant bone tumor occurring in mostly children and young adults affecting mainly the long bones, pelvis and chest. The prevalence of Extraskeletal Ewing’s sarcoma involving the lung is very rare. Fewer than three cases of Ewing’s Sarcoma complicated by hemothorax have been reported in the literature. We are describing a rare case of Ewing’s Sarcoma with an initial presentation of spontaneous hemothorax. CASE PRESENTATION: A 34 year-old Caucasian female presented with a sudden onset of severe right sided pleuritic chest pain associated with dyspnea. She had a history of resected Ewing’s sarcoma of the the right femur in remission over the past 10 years. Physical examination was unremarkable except for reduced breath sounds in the right lower lung zone. CT chest showed a 5cm mass in the right major fissure, a right pleural effusion and right hilar lymphadenopathy. She was noted to have mild anemia and leukocytosis. Thoracentesis removed 500ml of sterile exudative and partially coagulated bloody pleural fluid. Video-Assisted thorascopic surgery was performed and several large blood clots were evacuated from the right major fissure. Immunohistochemical stain of the right pleural debris was positive for Ewing’s Sarcoma [Figure 1-2]. DISCUSSION: Hemothorax is a rare presentation of Ewing’s Sarcoma. All cases of hemothorax reported in literature were associated with ribs involvement, metastatic tumor of the lung or the diaphragm. Interestingly, there was no primary tumor found via thoracotomy in our present case. The mass-like foci in the right major fissure was found to be coagulated blood. The recurrence of Ewing’s Sarcoma after 10 years of remission is unusual. The absence of a mass lesion in the setting of a spontaneous hemothorax makes this a unique presentation. This presentation raised some concern for disseminated Ewing’s malignancy, for which, the Event-free-survival (EFS) rates at four years after diagnosis has been reported at 27%. Whole lung radiation and high dose chemotherapy may be beneficial to this group of patient. CONCLUSIONS: Spontaneous hemothorax is a rare presentation in Ewing’s Sarcoma. Clinicians should include this in the differential diagnosis of a young patient with a significant oncological history. Reference #1: Eroğlu A, K. I. (2004, August). Extraskeletal Ewing sarcoma of the diaphragm presenting with hemothorax. The Annals of Thoracic Surgery, 78(2), 715-717. Reference #2: Raney RB, A. J. (2000). Soft-tissue sarcomas of the diaphragm: a report from the Intergroup Rhabdomyosarcoma Study Group from 1972 to 1997. . Journal of Pediatric Hematology Oncology(22), 510-4. Reference #3: Paulussen M, A. S.-D. (1998). Primary metastatic (stage IV) Ewing tumor: Survival analysis of 171 patients from the EICESS studies. Annals of Oncology, 9, 275-281. DISCLOSURE: The following authors have nothing to disclose: Hau Chieng, Biplab Saha, Muhammad Imtiaz, Mohammed Shiekhmohammed No Product/Research Disclosure Information