Rapidly Progressive Primary Pulmonary Leiomyosarcoma Diagnosed by Endobronchial Ultrasound‐Guided Transbronchial Needle Aspiration: A Case Report

Primary pulmonary leiomyosarcoma (PPL) is a rare malignant tumour with a poor prognosis, particularly in unresectable cases. We report the case of an 82-year-old man who was referred for evaluation of an incidental chest abnormality. Chest computed tomography (CT) revealed a nodule in the left upper lobe and enlargement of the 4L lymph node. An initial bronchoscopic biopsy was inconclusive; however, leiomyosarcoma was subsequently diagnosed using endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of the lymph node. The patient later developed a solitary brain metastasis detected by brain computed tomography and was treated with Gamma Knife radiosurgery, followed by chemotherapy. Despite treatments, the disease progressed rapidly, and the patient died 4 months after the initial diagnosis. This case highlights the diagnostic value of EBUS-TBNA in obtaining adequate tissue for definitive diagnosis of rare pulmonary sarcomas and illustrates the aggressive clinical course of PPL with brain metastasis.