Fig. 4

Usual interstitial pneumonia. a Chest radiograph showed patchy distribution of areas with consolidation and a fine reticular pattern, most pronounced in the periphery of both lungs. b A crazy-paving pattern was visible with scattered distribution. Superimposed on the ground-glass opacities a linear pattern with multiple small irregular lines was visible (intralobular fibrosis) (1). Traction bronchiectasis was seen in the periphery of both lungs (white arrow). c Radiological-histopathological correlation. On histology, thickening of the interstitium (arrow) with variable severity was seen, leaving some alveolar septa almost completely normal, whereas others were thickened. Fibrinous exudates, honeycombing (*) and mild inflammatory alveolitis were also present