Adult-Onset Primary Pleura Ewing Sarcoma With Recurrent Pleural Effusion: A Case Report and Literature Review.

Extraskeletal Ewing sarcoma (EES) is a rare malignant tumour within the "Ewing family of tumours," first described by Tefft et al. in 1969. It accounts for less than 1 case per million, typically affecting adolescents and young adults. We report a rare case of pleural EES in a 42-year-old woman presenting with chest pain and low-grade fever persisting for one month. Physical examination showed decreased breath sounds in the right lung base on auscultation. Ultrasound demonstrated right-sided pleural effusion, an unusual manifestation of EES that can hinder accurate diagnosis. CT scans identified multiple pulmonary nodules, further confirmed by thoracoscopy. Biopsy established the diagnosis of EES. The patient was subsequently treated with multi-agent VAC/IE chemotherapy. Despite initiation of systemic therapy, the disease followed an aggressive course, and the patient succumbed during follow-up. We also review existing literature to highlight clinical, pathological, and radiological features of pleural EES, aiming to expand knowledge of this rare presentation.