BACKGROUND The venous system of the posterior thoracic wall merges into a single trunk called the azygos vein, located in the posterior mediastinum, before draining into the superior vena cava. An aneurysm in the azygos vein is extremely rare. Such aneurysms are discovered as incidental radiology findings or while investigating a mediastinal mass. Visualization via bronchoscopy is atypical. CASE REPORT An 86-year-old female patient presented to the Emergency Department with a 5-day complaint of dyspnea and chest pain. She was admitted because of worsening condition leading to respiratory failure and paresthesias. She underwent endotracheal intubation and invasive mechanical ventilatory support. A chest X-ray showed a thickened mediastinum, tortuous thoracic aorta, and bilateral perihilar infiltrate with right predominance. Bronchoscopy revealed bleeding along the right bronchus and a blue protrusion coated with white material at the entrance of the main right bronchus. A pulmonary computed tomography angiography confirmed the presence of an azygos vein dilatation. Culture of bronchoalveolar lavage revealed Aspergillus fumigatus. CONCLUSIONS Bronchoscopy as a diagnostic method allows clinicians to verify the state and permeability of the airways during investigation of azygos vein aneurysms, which are rare entities but should be considered in the differential diagnosis of mediastinal masses and may be complicated by fungal pathogens such as Aspergillus fumigatus mostly in immunocompromised patients.