{Reference Type}: Case Reports {Title}: Intrathoracic Ewing's sarcoma in an adult masquerading as lung abscess. {Author}: Lahiri R;Rawat SS;Srikant K;Rao S; {Journal}: BMJ Case Rep {Volume}: 17 {Issue}: 1 {Year}: 2024 Jan 31 暂无{DOI}: 10.1136/bcr-2023-256631 {Abstract}: Intrathoracic extraskeletal Ewing's sarcoma (EES) is a relatively uncommon malignant tumour. Here, we present a scenario involving an adult man in his 20s with a large intrathoracic EES that manifested as a lung abscess. Preoperative diagnostic tests were inconclusive; hence, the patient underwent an exploratory thoracotomy for the excision of the mass. Histopathology revealed a small round blue cell tumour, and immunohistochemistry, along with fluorescence in situ hybridisation, confirmed the diagnosis of Ewing's sarcoma. Adjuvant chemoradiotherapy was recommended, but the patient did not comply. A year later, he presented with a recurrence of the intrathoracic mass and subsequently received adjuvant chemotherapy. Currently, he is in remission.