*Algorithm to approach a patient with cystic lung disease.* Consider atypical presentation of one of the major DCLDs or another cause (eg, amyloidosis, light chain deposition disease). AML angiomyolipoma; BHD Birt-Hogg-Dubé syndrome; DCLD diffuse cystic lung disease; LAM lymphangioleiomyomatosis; LIP lymphoid interstitial pneumonia; MAPK. mitogen-activated protein kinase; PLCH pulmonary Langerhans histiocytosis; TBBx transbronchial biopsy; TSC tuberous sclerosis complex; VAT video-assisted thoracoscopy; VEGF vascular endothelial growth factor. *#medlung Talks🫁* DOI: 10.1016/j.chest.2024.08.008