A 62-year-old woman with progressive shortness of breath on exercise. Chest radiograph and CT were undertaken. Chest radiograph showed a patchy distribution of areas with increased lung density (Fig. 3a) . There was also an increase in linear markings in both lungs. On CT, a crazy-paving pattern was seen with a geographic distribution. Some of the lines were thickened interlobular septa. Centrally in the secondary pulmonary lobule we could also see a spider of lines: thickening of the intralobular septa. These findings were seen predominantly in the upper lung areas (Fig. 3b) .