A Rare Case of Extraskeletal Ewing's Sarcoma Presenting as Hemorrhagic Pleural Effusion

Background: Extraskeletal Ewing’s sarcoma (EES) is a rare and aggressive small round cell tumor, primarily affecting soft tissues outside the skeletal system. Pulmonary involvement is uncommon, and hemorrhagic pleural effusion as an initial presentation is exceedingly rare. Due to its rarity, EES is often misdiagnosed, particularly in endemic regions where tuberculosis is prevalent.  Case Presentation: We report a case of a 33-year-old female with no known comorbidities who presented with progressive breathlessness, chest pain, and chronic dry cough for three months. She also reported intermittent fever and unintentional weight loss. Initial imaging suggested a right-sided pleural effusion, which was hemorrhagic on thoracentesis. Pleural fluid analysis revealed an exudative effusion with a lymphocyte-predominant cytology but was negative for malignancy. A contrast- enhanced CT (CECT) thorax demonstrated a large heterogeneously enhancing mass involving the parietal pleura, with adjacent rib erosion. Pleural biopsy and immunohistochemistry confirmed the diagnosis of EES. The patient was initiated on combination chemotherapy, resulting in a significant reduction in tumor size on follow-up imaging.  Conclusion: EES should be considered in young adults presenting with unexplained hemorrhagic pleural effusions. Early recognition and histopathological confirmation are critical for timely intervention. Multimodal therapy, including chemotherapy, surgical excision, and radiotherapy, remains the mainstay of treatment.