a) High-resolution computed tomography (HRCT) scan of the chest at the lung window level from patient 1 showing a characteristic nodulocystic pattern at the time of pulmonary Langerhans cell histiocytosis diagnosis. b) Serial HRCT 2 years later, while the p... a) High-resolution computed tomography (HRCT) scan of the chest at the lung window level from patient 1 showing a characteristic nodulocystic pattern at the time of pulmonary Langerhans cell histiocytosis diagnosis. b) Serial HRCT 2 years later, while the patient was weaned off smoking, shows virtually complete resolution of pulmonary lesions. Gwenaël Lorillon, and Abdellatif Tazi Eur Respir Rev 2017;26:170070 ©2017 by European Respiratory Society