A rare cause of airway obstruction: Mediastinal cyst secondarily infected with <i>Mycobacterium tuberculosis</i>

Mediastinal cysts are mostly congenital, but rarely, infections and malignancies can cause cystic degeneration of enlarged mediastinal lymph nodes. Diagnosis is challenging as the presenting symptoms are nonspecific. Surgical resection is the reference modality both for diagnosis and management. Secondary infection of mediastinal bronchogenic cyst with Mycobacterium tuberculosis is rare. Herein, we describe a young male who was managed as bronchial asthma with inhalational bronchodilators and glucocorticoids. Computed tomography revealed a cystic lesion in the subcarinal region. Endobronchial ultrasound-guided transbronchial needle aspiration was done to perform diagnostic and therapeutic aspiration of the cyst that showed infection with M. tuberculosis. A subsequent surgical resection confirmed the cystic lesion to be a bronchogenic cyst.