Abstract Background Cystic lung diseases such as lymphangioleiomyomatosis (LAM), Birt-Hogg-Dubé syndrome (BHD), desquamative interstitial pneumonia (DIP), and lymphoid interstitial pneumonia (LIP) share overlapping clinical and imaging features, yet longitudinal functional data remain limited. This pilot exploratory analysis aimed to characterize baseline physiologic patterns of patients with cystic lung diseases enrolled in the Baylor College of Medicine (BCM) Interstitial Lung Disease (ILD) Registry and to inform a future, larger scale longitudinal study. Methods Patients with confirmed diagnoses of LAM, BHD, DIP, or LIP were identified from the BCM ILD Registry (2018 to 2025). Data extracted included demographics, pulmonary function tests forced vital capacity percent predicted (FVC%), forced expiratory volume in one second percent predicted (FEV₁%), and diffusing capacity for carbon monoxide percent predicted (DLCO%), high resolution computed tomography (HRCT) features, and echocardiographic findings. Given the small cohort size and heterogeneity, analyses were descriptive and exploratory. One way analysis of variance (ANOVA) was used to assess group level trends. The study was approved by the Baylor College of Medicine Institutional Review Board (IRB# H-46740). Results Seventeen patients met inclusion criteria: 10 (59%) with LAM, 3 (18%) with BHD, 1 (6%) with DIP, and 3 (18%) with other cystic ILDs. Mean FVC% was 92.6 ± 22.8 for LAM, 81.5 ± 12.6 for BHD, 80 for DIP, and 61.1 ± 37.1 for other ILDs. FEV₁% followed a similar pattern, with values of 87.8 ± 27.3, 74.7 ± 9.6, 89, and 56.2 ± 32.0, respectively. Corresponding DLCO% values were 67.6 ± 22.1, 72.5 ± 22.0, 55, and 29.3 ± 8.4. Differences in FEV₁% (p = 0.47), FVC% (p = 0.42) and DLCO% (p = 0.17) were not statistically significant, consistent with expected variability in a small exploratory cohort. Conclusion This pilot exploratory case series provides an initial characterization of cystic lung disease phenotype in a single center ILD registry. Although statistically significant group differences were not observed, trends toward reduced DLCO in specific phenotypes underscore a knowledge gap in diffusing capacity patterns among cystic lung disease. These findings support the need for an expanded longitudinal study to define functional trajectories, imaging correlations, and molecular mechanisms underlying gas exchange impairment. This abstract is funded by: None
Galecio et al. (Fri,) studied this question.