A 39-year-old male patient, a leather trader by profession, presented with a 6-month history of dyspnea, hypox-emia, and digital clubbing. He had a 30-pack-year smoking history. Laboratory test results were unremarkable. Pul-monary function tests showed a severe decrease in DLCO (49% of predicted) and FVC (64% of predicted), suggestive of restriction. An HRCT scan (Figure 1) showed poorly defined micronodules with subtle pseudocystic airway changes, and mild patchy septal thickening in the upper lobes. Other findings were centrilobular and paraseptal emphysema and bronchial wall thickening. Patchy ground-glass opacities (GGOs), with fine reticular elements and containing small areas of bronchiectasis, were observed in the lower lobes. A coronal reconstruction clearly showed the coexist-ence of smoking-related findings: centrilobular nodules in the upper lobes, typical of respiratory bronchiolitis (RB); interlobular septal thickening, characteristic of RB-associated interstitial lung disease (RB-ILD); centrilobular and paraseptal areas of attenuation, as seen in emphysema; and patchy GGOs and cysts in the lower lobes, suggestive of desquamative interstitial pneumonia (DIP)-like elements. Bronchoalveolar lavage, performed in the right upper lobe, revealed 82% pigment-laden macrophages (although RB-ILD overlaps with DIP, they differ in their ex-tent/distribution). As reported in the most recent American Thoracic Society/European Respiratory Society state-ments,(1,2) multiple patterns on HRCT can be observed in the same smoking patient. Therefore, the radiologist can truly make a difference in the final diagnosis.
 




RECOMMENDED READING

1. Travis WD, Costabel U, Hansell DM, King TE Jr, Lynch DA, Nicholson AG, et al. An official American Thoracic Society/European Respiratory Society statement: Update of the international multidisciplinary classification of the idiopathic interstitial pneumonias. Am J Respir Crit Care Med. 2013;188(6):733-48. http://dx.doi.org/10.1164/rccm.201308-1483ST
2. Sverzellati N, Lynch DA, Hansell DM, Johkoh T, King TE Jr, Travis WD. American Thoracic Society-European Respiratory Society Classification of the Idiopathic Interstitial Pneumonias: Advances in Knowledge since 2002. Radiographics. 2015;35(7):1849-71. http://dx.doi.org/10.1148/rg.2015140334