Abstract Introduction Rapidly progressive cystic cavitary lung disease during transplant evaluation presents a diagnostic and management challenge. Identifying infectious etiologies—particularly nontuberculous mycobacteria (NTM)—is critical, as active infection significantly impacts candidacy and perioperative risk. Integration of microbiologic, physiologic, and radiographic data enables individualized risk assessment and transparent listing decisions. Case Description A 71-year-old man with COPD and chronic hypoxemic respiratory failure underwent lung transplant evaluation. He required 2 L/min oxygen at rest and up to 8 L/min with exertion. Six-minute walk distance was 440 m on 8 L/min. Baseline spirometry showed FVC 2.15 L (49% predicted) and FEV1 1.76 L (53% predicted), which remained stable on repeat testing. Diffusing capacity declined from 27% to 23% predicted. High-resolution CT demonstrated bilateral upper-lobe cavitary disease with multiple nodules on a background of emphysema and reticulocystic change. The largest cavities measured approximately 7.0 × 5.6 cm (right upper lobe) and 6.0 × 5.0 cm (left upper lobe) (Figure 1). Induced sputum cultures grew Mycobacterium avium complex (MAC); Mycobacterium tuberculosis NAAT was negative. Susceptibility testing revealed macrolide sensitivity with low minimal inhibitory concentrations to rifabutin and clofazimine, and resistance to rifampin and streptomycin. He had previously received isavuconazole for presumed fungal colonization. Echocardiography and right-heart catheterization showed preserved left ventricular function and no pulmonary hypertension. Given active MAC infection, limited diffusion capacity, and high oxygen requirement, the multidisciplinary committee deferred listing and recommended targeted antimycobacterial therapy before reassessment. Discussion This case illustrates the complexity of lung transplant evaluation in the setting of active NTM infection. Culture confirmation of MAC and detailed susceptibility testing guided therapy selection and excluded tuberculosis. Despite preserved spirometry, declining diffusion capacity and large cavity burden indicated advanced parenchymal destruction with poor physiologic reserve. Active infection and high oxygen dependency prohibited immediate transplantation due to risk of perioperative dissemination. Multidisciplinary evaluation prioritized infection control and re-evaluation post-therapy. This case emphasizes the importance of integrating imaging, functional testing, and microbiologic data to inform candidacy decisions and optimize outcomes in patients with cavitary MAC disease. This abstract is funded by: None
Muldiiarov et al. (Fri,) studied this question.