Pulmonary Mycobacterium Avium-Intracellulare Complex Infection in an Infant: A Silent and Coincidental Finding

An 11-month-old healthy infant girl was noted to have left lower lobe (LLL) opacities on chest X-ray (CXR) after developing desaturations during an elective cochlear implant surgery. Repeat CXR 10 days later revealed hyperexpansion of the left lung and persistent LLL opacity. Chest computerized tomography revealed enlarged mediastinal lymph nodes, left mainstem bronchial obstruction, and nodular opacities. Bronchoscopic biopsy of the endobronchial tissue revealed multiple necrotizing granulomas and grew Mycobacterium avium-intracellulare, Streptococcus viridans, and Actinomyces odontolyticus. This case illustrates the potential for significant mediastinal lymphadenopathy, and endobronchial and parenchymal lesions caused by nontuberculous mycobacteria, which can present insidiously and without respiratory symptoms in otherwise healthy infants, despite advanced pulmonary disease.