A 75-year-old man known to have bronchioloalveolar carcinoma. Chest CT showed a patchy distribution of areas with increased density, areas of ground-glass opacification and areas with consolidation. Superimposed on these areas there was a reticular pattern (Fig. 15 ). These lines correspond to a thickening of the interstitium. The diagnosis was made based on biopsy, which was not performed in our institution.