Fatal Persistent Cavitary Mycobacterium avium Complex Pulmonary Disease in a Non-HIV Patient With Prior Malignancy.

Mycobacterium avium complex (MAC) pulmonary disease most commonly occurs in patients with structural lung abnormalities or impaired cellular immunity and generally follows a chronic, slowly progressive course. Risk factors for disease progression and recurrence include cavitary disease, persistent structural lung abnormalities, and incomplete treatment courses. Although recurrence is common, progression to respiratory failure and death remains uncommon among non-HIV patients. We report the case of a 71-year-old female with a history of recurrent MAC pulmonary infection, bronchiectasis, colon cancer treated with surgical resection and chemotherapy, remote bone malignancy, hypertension, hyperlipidemia, and iron deficiency anemia who presented with progressive dyspnea, productive cough, weight loss, and generalized weakness. Computed tomography of the chest demonstrated extensive bilateral cavitary lesions, pulmonary nodules, and bronchiectasis. Sputum cultures confirmed recurrent MAC infection. Despite initiation of guideline-directed therapy with azithromycin, rifampin, and ethambutol, the patient experienced progressive respiratory deterioration requiring mechanical ventilation and ultimately died from respiratory failure. This case highlights the potential for recurrent MAC pulmonary disease to follow an aggressive and fatal course in non-HIV patients, particularly in the setting of structural lung disease, prior malignancy, and prolonged interruptions in therapy. Early recognition and sustained treatment adherence remain critical to improving outcomes.