Concurrent Smoking-Related Interstitial Lung Diseases in a Single Patient

The three smoking-related interstitial lung diseases (ILD) include desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), and pulmonary Langerhans cell histiocytosis (PLCH). They are considered discrete entities, yet it is not unusual to find a mixture of pathologic features rendering the histopathologic diagnosis difficult. It is uncommon to have overlap in the different radiologic findings between these diseases. We present a unique case, in that the extent of DIP and PLCH-like changes were manifested both histologically and on high resolution computed tomography (HRCT) with ground-glass attenuation and upper lobe cystic changes suggestive of both diseases.