Great observations so far! Many of you correctly identified the diffuse ground-glass opacities and mild mosaic attenuation in the lower lobes as representing desquamative interstitial pneumonia (DIP), and the ground-glass centrilobular nodules in the upper lobes as respiratory bronchiolitis (RB).

But let’s not overlook the centrilobular nodules of soft tissue density, the thick-walled cysts, and reticulations in the upper lobes. What could these findings represent?

I’d love to hear your thoughts—what process ties these upper lobe findings together?