[Mycobacterium avium infection presenting as a mass in the right lung]

The diagnostic procedure of pulmonary masses in patients with AIDS is presented.

A 39-year-old patient with AIDS was admitted to hospital because of a non-productive cough and radiologic evidence of mediastinal and right hilar masses suggestive of lymphoma associated with pneumonia of the right lower lobe. Bronchoscopy revealed a stenosis of the right lower lobe bronchus with small endobronchial lesions. Biopsies showed granulomatous inflammation, but no microorganisms were detected. Chest pain with dyspnea developed and was relieved by evacuation of pus during mediastinoscopy. The diagnosis of Mycobacterium avium infection was established via culture of sputum and bronchoalveolar lavage fluid and via mediastinoscopy. The patient was commenced on a 3-drug regimen with rifabutin, ethambutol and clarithromycin and has remained asymptomatic now for over 9 months.

Mycobacterium avium infection needs to be included in the differential diagnosis of patients with AIDS presenting with mediastinal and hilar masses. When procedures such as bronchoscopy and chest CT-scans are non-diagnostic, mediastinoscopy may become necessary in order to establish the diagnosis.