Figure 1. Serial chest radiographs of a 77-year-old man who presented with progressive cough and shortness of breath for 2 days. (A) Initial chest radiograph performed on admission showed a right perihilar opacity (thin arrow), in keeping with known chronic middle-lobe collapse of uncertain etiology. There was no ground-glass opacity, consolidation, or pleural effusion. (B) A follow-up radiograph performed 10 days later showed interval development of subtle increased reticular opacities in the right lower zone (broad arrow). There were bilateral small pleural effusions (arrowheads).