A 42-year-old woman presented to the outpatient Pneumology Clinic with a complaint of a persistent cough without fever over a month and the onset of chest pain a week prior to presentation. A chest X-ray revealed a left-sided perihilar opacity (Figure 1A). She reported a negative medical history and was prescribed the antibiotic levofloxacin. Computerized tomography (CT) of the thorax demonstrated a solid mass (10x12 cm in diameter) in the left upper lobe, as well as enlarged superior mediastinal and aorto-pulmonary lymph nodes (Figure 1B). Positron emission tomography demonstrated pulmonary neoplasm with a standardized uptake value of 31 and mediastinal lymphadenopathy. Fibrobronchoscopy and EBUS-TBNA were performed in the outpatient clinic, aimed at diagnosing and staging the probable lung tumor. Using a 21-gauge needle, she underwent a bronchoscopy with EBUS-TBNA of subcarinal lymph node stations (nodal station 7) and suspicious histopathological tissue at the upper left bronchus. The procedure was performed under deep sedation using midazolam and propofol; however, resistant cough was noted. Upon completion of the procedure, she complained of acute chest pain, which regressed immediately, and a physical examination was negative following which she returned home. Cytological results of all biopsies obtained with EBUS-TBNA were negative. CT-guided fine-needle aspiration (FNA) performed 3 days later revealed a right-sided pneumothorax associated with a small pneumomediastinum (Figure 2). The patient was admitted to the Department of Internal Medicine for 4 days of observation and responded to conservative management. Based on extranodal dissemination, the cytological samples obtained via FNA that were positive for non-Hodgkin's diffuse large B-cell lymphoma, were later classified (staged) as samples showing a stage IV tumor. We obtained the patient's consent to publish this case report.